Why and How to Relay Headlights

[@StereoSquared]

Thank you so much for being the first person to explain this so that a newbie like myself can fully understand it.. One question: I have connected two 5pin relays one for low beam and one for high beam and both work perfectly Can ai take a connection from pin 86 on the high beam relay( this wire comes from high beam stalk on steering column) to pin 86 on a third relay(powered independently) for two spotlights..TIA

[@bwcordes]

I daisy chain the trigger and the ground on the relays all the time. It makes for a neater wiring situation and fewer points of failure in my opinion. Thanks for the kind words, and the view!

[@charlesfields7908]

Definitely answered my question as ive replace my light switch 4 times since 2019. Plus my connector at the switch melted back in 07 when my original switch failed.

[@bwcordes]

Great. Glad I was able to answer your questions. Thanks for the comment, and the view.

[@RubenRamos-x2w]

Good video, is it possible to jump from 87 to the rest of your nighttime running lights.thanks

[@bwcordes]

Absolutely. I've wired up cars to always have the fog lights on when the low beams are on by jumping power from the low beam relay to the fog light relay. You could take off of the 87 terminal to power the other lights, but I would just as soon use the trigger for the other trigger. Now, if you're wanting to use the terminal 87 to just power the other lights, I would just be sure that your relay and wiring is up to the task of the added amps. As a disclaimer, always be aware of your local laws for things like this. There are some silly rules that can can get you a big ticket in some places.

[@davidyj9013]

@ 17:36 you mentioned terminal 87a but didn't say if you were talking about a 4 pin or 5 pin relay. I have a '90 LeBaron with headlight problems so decided to install a relay. My problem is the schematic embossed on the side of my 4 pin relay cover shows 85, 86, 87, & 30. However, the four 1/4" male spade terminals are labeled 85, 86, 87, & 87a. Does the 87a spade terminal equate to the 30 as shown on the relay cover? No one has responded to this question. Is it because nobody knows the answer to this question and would be embarrassed by saying so? Or do the many video instructors out there simply not care?

[@bwcordes]

There seem to be endless variations of the "Bosch Style" relay. Generally speaking however, if it's a 4 pin relay, then you have the 85, 86, 30, and 87 terminals only. The 5 pin relays are most often the 87/87a style. As I hope I mentioned in the video, I use dual 87 terminal 5 pin relays so I don't have to splice the wire coming off of pin 87. I have moved to using relays with a diode in them to prevent the flyback voltage from freaking out my older electronics. They're a noticeable difference in my early cars when using very high wattage bulbs. I have been ordering the Hella units from Susquehanna Motorsports. They had to order them for me last time, but it didn't take long, were reasonably priced, and the only ones I could find so it was a relatively painless choice. I hope all that helped.

[@timwilsononline]

Absolutely excellent - thanks for taking the time to put this together. It was really easy to follow along and understand what you're doing. I was actually scouting for info info to help me with wiring accessories up on my bike (e.g. Hella Supertone horns). The practical example of your car headlights is all completely transferrable. I didn't know the reasons for relaying a lighting circuit, or the relationship between light output and voltage. Really great to know. THANKS!!

[@bwcordes]

Glad the video was a help, Tim. Thanks a ton for the comment.

[@mikevandervoort3231]

You could have used 2 different relays that had 86, 85, 87, 30 & 87a. If you would have hooked up your low beams to the 87a on both relays then, they would have turned off when you hit your brights, like most cars - if that is what you wanted to do. Being that the relays you had came with a kit, I understand why you didn't. Good job, well done! - just an observation.

[@bwcordes]

That's true. Depending on what headlight/high beam switch the car has that could be the better way to do it. Another option is to use that strategy to turn off the fog lights when the high beams come on. With all the different relays out there the possibilities are endless.

[@boomwithpeter623]

Got an old (18y old clio 1.4 16v 2001 with 110hp) car (car is old as me lol) for myself, problem is it doesnt have automatic lights and since its an expensive ticket for not having your lights on (in europe you need to have lights on day and night) so i connected a relay to my light swich and key ignision position. What i wanted to say is that i can leave the switch in on position and remove the key and the lights would turn off, same as if i put in ignision positon my key they will turn on... Thank you for your video, i used 4mm thick silicon wires (for space heaters) for this

[@bwcordes]

That's a great solution. Thanks for taking the time to post up about it.

[@t.ticklesfpv]

thank you!! my old ranger is going to be not so night blind

[@bwcordes]

Glad to hear it. We had a ranger way back when and it was a great truck for sure. Thanks for the comment, and the view.

[@chui19801]

OMG. I truly needed a video like this to make it logical. I just recently put LED Halo lights on my 66. From one day to another, the headlight won't turn on. I order a headlight switch and pruuum, back on the road. I decided to put relays, now, one side won't turn on. My luck. I tried to be fancy and install a relay for low beams and a relay for high beams. I am stuck now. One side won't turn on. LOL. I have 4 headlights

[@bwcordes]

I always start at the headlight connector and work my way back. I use a "Load Pro" which pretty quickly tells me if I have a problem with resistance, open circuit, or a bad ground. I then work my way back to the relay. You did make sure to use a dual 87 pin relay, or made sure to splice two wires off of pin 87 when running them to each side, correct? Though, I suppose if you used 87a, it would be on when the switch was off. There are some funky relays out there though, so who knows.

[@terrancegrant1664]

Great video; I need the relay you used as an example. I currently have the 87a version, which is junk...for the reasons you alluded to.

[@bwcordes]

If you type in "Hella dual 87 relay" into Amazon's search bar you should come up with some options. Go with at least 20A for the current rating on it and you should be all set.

[@AzraelPercussionNEO]

THANK YOU THANK YOU THANK YOU for an ACCURATE THEORETICAL EXPLAINATION IN A NUTSHELL so to speak

[@bwcordes]

You're welcome. I'm glad you found it useful.

[@AzraelPercussionNEO]

bwcordes Alot of other videos don't explain the fact that Power Output is expotentially increased and thus as a result Resistance is decreased as you show with first simplfied graph of Exponential increase of Power Output. Another thing you pointed out is that current decreases as the length of the wire increases (the fundamental concept of DC Voltage). Very well explained as depicted with the Devin simplified graph. :))))

[@kawshaldinnoo208]

Hii from Mauritius.... Great uploads of your videos... Joined your channel i guess around 6 months ago and I have watched quite a lot of videos.. I have an issue concerning my car... I'm wiring the alarm siren to the car horn... So that when the car is armed or disarmed.. The car horn sounds once or twice... I completed the wiring.. and it worked... The only issue I have is that the car horn is sounding too loud... Wat can i do to make it lower so tht when i arm the car... My neighbors won't be cursing me.. 😅 Thanks.

[@pprotory]

Easiest way is to use a different horn. Most American cars just use the cars actual horn at the same volume to arm while most German cars have a regular horn and then an alarm horn (sometimes just an additional wire for the actual horn.) for arming at a lower volume. You could try installing a potentiometer or a resister as well between the horn power being fed from the alarms relay. A potentiometer is used to increase/decrease current and you can get them in a variety of styles. Some car horns have adjustment but be warned as that adjusts the horn for all operations.

[@brigond1]

I bought and installed a relay harness from Dapper lighting. Its a 5 minute plug in installation. 1971 charger with 4 headlights and flip headlight doors. Lights and doors function normally when the brights are on but when the low beams are on the doors remain open. The doors wont close after shutdown unless i switch to brights before shutting down. This video is 9 years old, is that baby still running and driving ?

[@bwcordes]

That's interesting that they won't close unless the brights are engaged first. Cool that you found a good solution though. The 90 shadow was mostly rust when I made this video, and it has long since been scrapped. I'm currently driving an 89 Shelby CSX for a daily driver, and have another one tucked away in the garage. I think those are what I'll drive for the rest of my life. Thanks for the comment, and the view!

[@BAHRacingTeam]

Building a drag race only 1989 mustang. Car has no wiring so I’m starting from scratch. I ordered new light bulb plugs for the headlights, marker lights and running lights. Can these be wired together and ran to a relay with a toggle switch?

[@bwcordes]

You want to give yourself some headroom with the relay for the amperage of all those lights, but it could certainly be done that way.

[@BAHRacingTeam]

@@bwcordes what size 30 or 40 amp, four or five pin relay? I plan to run a relay on each side

[@bwcordes]

@@BAHRacingTeam You'll want to do the math based off of the wattage to be sure, but a 30 amp relay should definitely cover it for some running lights and a normal headlamp. I just run the bosh style relays. They're cheap and everywhere. If you get some dual 87 pin relays you wouldn't have to have as many splices for the running lights. Either way will work though.

[@sethelable]

“Let me switch to this super science graph” lol love the video. Good info and well presented.

[@bwcordes]

Thanks for the kind words and the comment Seth. I appreciate it.

[@stephendrahos9000]

Great video. So I purchased this kit. Two questions: 1. What size fuse is recommended (terminal 30)? 2. At 14:20 you connect the driver side headlight to 86 on Relay No. 1 (low) and Relay No. 2 (high). Makes sense so as to trigger to relays. So then no need any wire from the passenger side to 86 at all? Just cut/disconnect on the passenger side and wrap to avoid shorts?

[@bwcordes]

I use 20 amp fuses. That's correct. I use the wiring from the driver's side of the car to trigger the relays. I disconnect the wiring on the driver's side and tuck it back to the original harness. I don't cut anything off, and I generally use a mating connector with nothing in it just to make sure it can't short out on anything. If you wanted to cut it off, you could just use the crimp on caps to protect them.

[@stephendrahos9000]

@@bwcordes Many thanks for the quick relay. Thanks for confirming. And I believe I am going to use the stock ground wires from the original pigtails instead of running separate ground lines from each headlight to the negative post of the battery like you did. Two less lines to run (even though you're right, it will be would be a better, more secure ground). Your thoughts?

[@bwcordes]

@@stephendrahos9000 That's what I've been doing lately. It works really well, and I haven't had any problems with it. I've actually been running one ground wire to the relays and daisy chaining it over to the other relay blocks. You need hardly anything for the ground on the triggers, so it makes the wires much more manageable and a neater final appearance.

[@howtobeatspammers]

Great video!! I cracked up when you introduced your exponential curve video! Thanks for making a boring topic, FUN

[@bwcordes]

I'm glad you enjoyed it. Thanks for watching!

[@jmmedina0211]

Kinda late and idk if u could help me out but I changed my front end on my gmc c1500 1988 and put composite headlights so i changed the headlight connectors to 9005 and 9006 recently while driving my headlights flicker alot off and on and i turn them off with the switch and then on and they stay on for a little bit of time and then they turn off and on.. i changed fuses and headlight switch and still does it anyone know why thay could be happening? Stock headlights btw

[@bwcordes]

I'm thinking it's either too much resistance or perhaps a poor ground. I've become a fan of the Load Pro recently, as it helps to determine if either of those is present in mere seconds. However, since you're already using headlights, checking with a high beam in line between the power and ground might show the issue. A simple check of continuity, or resistance won't do the job because you need a load on the circuit to show the fault in a situation like this. The Load Pro puts a 50ohm load on the circuit and you measure the voltage drop to see if it's too high. Hope this helps.

[@gogetassj4874]

But my car is a 1976 Plymouth volare the wiring is old but in good shape I could do the relay conversion if I choose to do so right it’s not going to harm anything and it will work just fine right just to be on the safe side thank you for you’re expertise and you’re time

[@bwcordes]

I know that the old Chryslers tend to melt the headlight switches on occasion. The relays would be a good way to isolate the current from inside the car.

[@MrBerenguer67]

Hi I have problem whit my fog lights the switch turn on and the lights not I have a red wiring on the battery whit fuse and other wiring orange this one I check on the relay is don't have power when I turn on what you thing the bulbs all ok thank you very much

[@edgarbarbosa8076]

hi i just got HID for a 2005 scion xa ..i installed them but when i put high beams on they go out would it be because i need a relay ..thanksthanksb if u kan helps

[@bwcordes]

+Edgar Barbosa HIDs should pull less current than a standard bulb. I would double check your wiring, especially the ground and then I would be questioning the kit.

[@edgarbarbosa8076]

+bwcordes I shocked the wire n move them around I tride them in different patterns... when they turn on the high and low beam r on and the sitting is on low ....ones I turn on the high beams they just go out like if the fuse was burn but it's not ..thin I turn them off and back on and come back on ...

[@jbmjbm323]

+Edgar Barbosa You probably need 2 relays, one for the low beams and another one for the high. So that you have 2 different power sources that turn on and off from the high and low.

[@wzystkocokham7333]

iF YOU JUST DROP A RELAY ON THE GROUND SAY BELT HIGH. IT WILL RETURN TO ITS ORIGINAL SETTING AND WORK

[@walterjabillo918]

Does both the 87 output,follows with polarity,i did this diagram,unfortunately only 1 light lit,and not on the other one

[@bwcordes]

If they're both terminal 87, it should work. If one terminal is 87, and the other is 87a, then only one will be switched at a time.

[@walterjabillo918]

@@bwcordes it is both 87,if thats the matter,maybr ill check the polarity on the other light,but i did what is in the diagram

[@bwcordes]

@@walterjabillo918 I would suspect that, or a ground issue more than anything.

[@jiantjon]

Great video, this explains a lot! I do have one question, though. Any help would be greatly appreciated. I currently have my main headlights as my DRL and I am wanting to add some LED fog lights to run as the DRL instead. I have figured out how to get the LED lights installed and tie them into the fuse panel to turn on when the car is on (this is how I want it). My question is, how would I relay off of the parking lights with this kit? My headlights and parking lights automatically come on when it gets dark enough, so it seems that parking lights would be a good source to trigger the relay. Thanks in advance, and once again, great video!

[@bwcordes]

The relay will draw so little current that you should be able to tap into any power source you want in order to trigger the relay.

[@artyfuffkin7805]

Which way do you say current is flowing ? because you used the terms power and ground not Pos & neg

[@bwcordes]

That's a good suggestion. I made the video for folks with normal 12v systems, and I went with the most general terminology. I think most folks are looking at the positive and negative terminals on the battery while doing this, so that's how I did it. I really appreciate the feedback and the view!

[@artyfuffkin7805]

@@bwcordes DC current flows from the Neg to the positive. Many are confused on it equating ground to AC currents flow

[@artyfuffkin7805]

From what I got of your understanding , your not qualified for teaching auto electronics

[@bwcordes]

@@artyfuffkin7805 You're right. I'll leave the classes on theory to you, and I'll keep doing the how to videos. Thanks again for the feedback!

[@artyfuffkin7805]

@@bwcordes but I've got some relay ?s what is the bread board in a auto relay for

[@nickpeh1066]

How to determine the relay voltage & current enough for the accessory? Let's say headlight is 12v55/60w, relay selection would be anything above 12v & current above 10A? The fuse used from the connection to battery would be 2 times preferred?

[@05222007MER]

I realize this video is 6 years old, but I was wondering if a relay could take the place of a inline diode on a bow and stern light on a boat application. I bought the boat used and the wiring on the light switch is to crowded. Thank you!

[@bwcordes]

What type of lights are they? I know there are some relays with internal diodes to prevent the voltage spike when the magnetic field collapses as the relay is turned off.

[@gogetassj4874]

Hello I have led headlights do I have to add what you’re doing in the video to my headlights or since led draw so little power am I fine with just the stock setup they are 25 watts each or is it just better to do the relay that you explained in the Video please replay thank you for you’re information on the subject Thank you

[@bwcordes]

LEDs aren't dependent on voltage, and that's not a lot of amps to go through a headlight switch. Unless you have a very old vehicle with a wiring harness in very rough shape, I would skip the relay conversion.

[@joevignolor4u949]

My wife's Honda Civic kept having the headlights go off while driving at night. The car had been recalled for this back in 2011. Honda had routed all the headlight current through the headlight switch on the steering column. Over time this would cause heat damage to the switch. I added a relay, which now carries the headlight current and the switch only controls the relay.

[@bwcordes]

Thanks for the comment Joe. It's amazing to me how many companies ran all the current through the switch for as long as they did. It just doesn't make sense for so many reasons.

[@joevignolor4u949]

@@bwcordes Agreed. This is an especially dangerous situation. All of the external and internal lighting would be lost suddenly when the lone ground to the entire lighting system was lost due to thermal damage inside the headlight switch. The problem was being exacerbated because the hot air coming from the dashboard vent discharges directly onto the switch on the steering column. I reported it to Honda and told them they needed to do another recall because the problem is coming back but they just blew me off. I guess until someone gets killed in one of these vehicles they don't consider fixing it correctly to be worth the money.

[@bwcordes]

@@joevignolor4u949 Thanks for doing your part in contacting them at least. I'm perplexed as to why they would take on that level of liability, especially since know of people who had fires under the dash of their 80s and 90s Chrysler vehicles from this same issue. Then again, there's the airbags and other problems. It seems like it never ends.

[@joevignolor4u949]

@@bwcordes The problem is the car companies look at the costs of doing the recalls versus the potential liability of any accidents. This is what happened with the Ford Pintos back in the 1970's that the gas tanks would explode in a crash. The solution would to be to put executives who make these decisions in jail for manslaughter but that doesn't happen often enough. Unfortunately.

[@bwcordes]

@@joevignolor4u949 Indeed. It's like the scene in Fight Club where he describes how his job at the insurance company works.

[@husky1232]

Hello can 85 &86 be connected to a 2 pin switch or 86 to the switch and 85 from relay straight to metal on vehical body and from my switch 86 to switch and then connect earth wire to the other pin on switch to ground thank you for the video

[@jameswoodburn8852]

cool video, but you lost me at the end. you said you had to hook up your yellow wire to on of the 87, then run another wire from the 2nd 87 to the other head light. i'm assuming since your yellow was your high beam you would attach the second 87 wire to your high beam on the passenger side headlight, but you never mentioned were to hook the low beam or black wire in the video. please advise a.s.a.p. as i have my 98 dodge ram 1500 sitting outside with everything done exceptthe 87 hookups

[@joyaulph8441]

Jim. There are two 87 terminals on these relays, so each relay sends a wire off of an individual terminal 87 to the high or low beam (depending on which beam you're triggering). The third wire is ground. While I used the battery in this video, I have started to keep the stock ground, as they are short and seem to be efficient enough for the load. Thanks for the view and the comment.

[@WHISKEYTANGOFOXTROT93]

Hey thank you very much for the informative tutorial. I have one question. Should an inline fuse be installed between battery and relay connection? If not, do you know where? or if i need one?

[@bwcordes]

I install a fuse between the battery and the connection of the load carrying wire to the relay. I've used the inline fuse holders and a fuse block before with equal success.

[@winstonclarke535]

How far away, can you cut your high/low beam wires, to make your connection, thanks, Winston.

[@bwcordes]

If you're talking about the connection at the relay, you can cut them wherever convenient. If you're talking about reusing the stock headlight connector with the factory wiring, I would leave a few inches for your splice. However you can go pretty short if you're careful and it's absolutely necessary.

[@winstonclarke535]

shawn can a 14 guage wire be use throughout the system or do you have to use 18g also winston.

[@bwcordes]

You can use the larger 14ga wire for terminal 85 and 86. Those only power an electromagnet which pulls a tiny amount of current so it's not necessary.

[@MazMaslin]

I appreciate this is an old video, but can I use a relay to turn off a component when I turn on another powered by the same line? I want to run drls spliced from the sidelights that turn off when I switch the sidelights on... Possible?

[@bwcordes]

+AngryWelshman You should be able to do that. You'll need a relay different than that of the ones in the video. If you use a relay with an 87 and 87A terminal you can use the normally closed terminal to run the sidelights which you'll have to switch somehow. Then you can use the normally open 87 Terminal to feed your other lights. Since the normally open terminal 87 comes on when the 87A goes off you can effectively turn on one item while turning off another item. A lot of folks will use the terminal 87 and 87A in conjunction with one another if they live in an area which requires that fog lights turn off when high beams are turned on.

[@MazMaslin]

+bwcordes thank you brother, I'll takena closer look at this and see what I can come up with.. nice one, cheers again!

[@tomsteffs6511]

So im a little lost, would appreciate you clarify the two 87 terminals. You are running 2 relays with each having 2 terminals marked 87?. If yes that means you have 4 terminals marked with 87. Four wires from 2 relays, terminal 87 where do they go?,

[@bwcordes]

Great question. I run a wire for each side of the car off of each relay. One relay controls both sides of the car's low beams. The other relay controls both sides of the car's high beams.

[@cortesvd958]

On my chevy s10 the lights are not working low and high beams. The lights are hooked up to two relays the drl relay and another relay. I'm trying to run an additional switch to be able to turn them on and off while I try to fix the problem. Here are my questions...how many amps you recomend for the fuse to connect the power from the battery to the relay? can I hook the new relay to the existing wire? The switch I'm using it has three terminals and rated on 20 amps hope I'm using the proper one.

[@bwcordes]

It sounds like you are on the right track. Just make sure you leave a little head room on the relays. I usually buy relays which are rated for 40 amps and ensure that my wiring also has a little headroom for the amps they will be drawing. Thanks for the view, and the comment.

[@cortesvd958]

@@bwcordes thanks for respoding!! I found out that my problem is a faulty or bad ground. Now I'm getting around 12.5 v using the multimeter prong to the positive terminal of the connector and ground from the chassis. Question I'm still planning to add the switch using the existing wiring and have that extra option to turn the lights if I do this will that cause any damage? Basically It will be two power sources to the low and beam lights if that makes sense...

[@bwcordes]

@@cortesvd958 Multiple ways of controlling the lights shouldn't hurt anything.

[@rhexmartinez2348]

hi have a good day.. it is possible to put a capacitor? to stable the voltages needed even the wire is a long wire.. thanks

[@bwcordes]

You could, but I don't see what that would accomplish in regard to reducing the voltage loss over the wire, which is the main point of this.

[@DAVENMEMPHIS]

i`ve seen videos 87 going to pos. to battery,,30 to lights,, 85 ground,,86 switch,,,,and in some videos 87a turns somethings on when switch is turned off,,,and then there`s yours ,,,and 30 to pos. to battery,,,87 to lights,,,86 to switch,,,85 to ground with no 87a....... could you explain to me why is this please, i`m more confused now after watching all these videos

[@bwcordes]

dave nmemphis On most relays terminals 85 and 86 can be hooked up either way. 30 really should be your power in, but in some relays is doesn't matter. Terminal 87a is hot when the relay is not energized, and 87 is hot when the relay is energized. Some people use that feature for some pretty neat things. For example, you could kill your fog lights when you activate your high beams (as you're legally supposed to do in most states) with this little trick depending on how your stock fog lights get power, wattages, etc. There is a style of relay for about anything you could want to do. Even the relays shown in my video are a little different from most of them out there in that they have the two 87 terminals rather than just one or an 87 and an 87a. That's perfect for setting up headlights since you don't have to splice into the wire coming off of 87. Hope this helped. Feel free to ask any questions.

[@DAVENMEMPHIS]

that helped, thank you !!! so in other words there are differnt types of relays

[@bwcordes]

dave nmemphis Sure. I don't think I could start to put a number on the different types of relays out there. There are several very common ones used in the automotive industry. The style I'm showing here is a "standard" Bosch style relay. As you've seen there are several different styles of those even.

[@raybowman3963]

bwcordes

[@davianwalker1366]

i need some clarification... did you use 1 relay for high beam and the other for low beam? Or, Does each relay control 1 headlight?

[@bwcordes]

Yes, one relay for high and one fir the low beams. The original power wire for each now triggers the the relay.

[@davianwalker1366]

ok.. thanks alot 👍

[@skyboy123454321]

Think of relay as a switch. You need two switches to control H/L beams seperately.

[@geraldcrawford1707]

Davian Walker "

[@shovelrickshovelhead8713]

Shit me I hope I remember this, I saw relay lick

[@Fritsvrolijk]

Thanks and regards from Holland

[@bwcordes]

My first reply from Holland! Thanks a ton Frits!

[@tomsteffs6511]

Thanks for clarifying my last question, If you dont mind can i ask another question.Where can i find a relay with two 87 pins?, I looked everywhere and all the relays i come across are 87 and 87A, Thanks again

[@bwcordes]

I generally buy Hella relays off of Amazon, although the last time, they were out of stock so I purchased from a rally car supply place.

[@kevinhornbuckle]

Very educational. Also your presentation style is just right.

[@bwcordes]

Thanks for the kind words and the view.

[@brandoncartwright8829]

So adding a relay after the headlight switch, will the low beam and high beam still work?? About to do this on a 2nd gen dodge

[@bwcordes]

You need a relay for each. One for the high, and one for the low beams.

[@brandoncartwright8829]

@@bwcordes thank you, i realized that after watching

[@brandoncartwright8829]

I also notices he did a good drawing and explaining the pinout then mixed it all up when he was working on the car lol

[@bwcordes]

@@brandoncartwright8829 The polarity doesn't matter on the control side unless there is a diode in the relay. These don't have one, so I hooked it up in a way that let the wires lay down better.

[@brandoncartwright8829]

At 14:35 you said you took power to pin 86. Is that what you mean it doesnt have to be pin 30 for batt power

[@firstgenerationgarage2803]

Hi just finished watching your video very interesting just yesterday I took out on a night cruise my 1967 Firebird with a 455 the first time I ever drove the car with the headlights on since I restored it and I notice the fuse that I have on the main power wire going from my Junction block into the fuse box to the light switch that inline fuse was very hot I put a 30 amp inline fuse in front of the car by The Junction block it was so hot it was very uncomfortable to touch the plastic covering the inline fuse actually look like it was starting to melt and I only went for about 6 miles do you think a relay will help this problem checked all my grounds and everything is reading correct with my voltmeter same reading I have at the battery is the same reading I'm having throughout the car when I check it with the voltmeter my only guess is that I need a relay on this main power wire please can you help me I don't want my car on fire

[@bwcordes]

I definitely think the relay for the headlights would help. I'm not familiar with that car, but I do know that your headlights must be a pretty good chunk of that 30 amps while you're cruising. I'm honestly surprised that you only have a 30amp fuse for all that's going on in the car off of the main fuse block inside the vehicle. Does your heater go through that too? That'll pull a bunch of amps also.

[@Maples01]

I installed a relay harness, nothing, no headlights, got mad and pulled it, I checked it with my ohm meter to find nothing wrong, believe my issue could be where it grounds at the headlight socket, going to install a ground to body wire later and try again.

[@skyboy123454321]

grounding may be affected by poor metal contact due to plastic parts, paint etc.

[@LZDEN]

good project....im going to do this mod to my jeep xj very soon..thanks for the guide..;-)

[@darrylm3627]

first-time i heard of a dual pin 87 cool 😎

[@bwcordes]

Thanks for the comment Darryl. I hadn't heard of them for the longest time either, but now they're all I use for my headlights.

[@ceeattle]

Do you ever use copper clad aluminum wire

[@bwcordes]

I have not used it. I know there are people who will do so for weight savings, but I have never liked the idea. I have actually transitioned to Tefzel wire for the vast majority of my projects.

[@tomsteffs6511]

Sorry for being a pain, but can you complete a wiring like you did using 2 relays with only 4 pins?, or it it a "must " to use 5 pin relay?

[@bwcordes]

You can absolutely use relays with one pin 87. You'll just have to have splices so you can feed both sides for the high beams and low beams.

[@charliedee9276]

Or you could do it with one 4 pin and one 5 pin.

[@maar5725]

To prevent corrosion, rust and or oxidation on, relay pins junction box holes, connection, battery posts, wire or cable terminals and junction box hole ,,, ''' apply / add dap of silicon / dielectric grease . Also, it will ease insertion & removal of relays, fuses and any component that has pins and or legs .

[@TheGenteneire]

I don't undestand my bike have one relay why have i installing a second relay for the hid ballast ?

[@ignatuissampie8054]

Okay ...so I have two sets of wires for both headlights...do I use one set coming from light switch and just cut the other set off

[@bwcordes]

If you have two sets because there is one set for each side of the car, then yes. Use one set to trigger the relays and cut the other set off if you would like. You could also remove that set from the connectors if you don't want to cut the wiring. Be careful if you remove or cut the wiring under the hood. Those wires will still get power when the headlight switch is on, and could short to ground if you don't wrap them with electrical tape etc.

[@alanmcdowell977]

Do you have a wiring Diagram on a 2006-2008 hyundai santa fe

[@bwcordes]

Sorry, I don't. Although if you look up what type of bulb it takes, the wiring to that style of bulb is standard. Knowing that, you can see what color is what.

[@juanabreu5127]

In the video i see you are using 63/37 solder alloy, I understand, the 63/37 solder alloy has a lower melting point than the 60/40 alloy; should´nt it be better to used 60/40 alloy in the engine compartment.

[@bwcordes]

+Juan Abreu I've never had a problem with it.

[@Teal2nnr]

+Juan Abreu The 63 / 37 is the Eutectic (lowest melting point) for Tin / Lead alloy. With the Tin?Lead eutectic there is NO plastic state/phase between solid and liquid. SO, cold solder joints are less likely for the begineer. The 60/40 is standard formulation used for decades (strength versus melting temperature), has a slightly shiny solid state -- when compared to 63/37 alloy. It does have a "Plastic state" range of about 10 degrees -- if joint is moved during this phase - a cold solder joint results. There are advantages to some solder alloys (Tin, Lead, Silver, etc.) for higher melting temperatures, strengths, etc. IF you are using QUALITY soldering stations (Weller EC, TECP, WS series; Hakko 936 or new 888) you will likely not see many differences in usage. However, IF you are using bargain bin stick irons (NO temeprature control of tip) -- then soldering is very depedent on your skills and experience.

[@juanabreu5127]

+SavageTacoTime Thanks for the info.

[@BryanBabic]

What purpose does the second relay serve, or did I miss that you wired it for the high beam bulbs?

[@bwcordes]

That's correct. One for high beams and one for low beams.

[@slams777]

IF MY 67 DODGE CORONET WITH A 68 440 MOTOR AND STOCK ELECTRICAL WHAT COULD INDICATE PROBLEMS WITH THE RELAY THANKS

[@bwcordes]

What's the problem exactly? If you apply power and ground to the coil portion of the relay you should get a strong click that would indicate it's working.

[@slams777]

the lights work headlights work but one of the bright lights is going on when I hit the brights and the other ones so there's only three lights activated

[@bwcordes]

Have you checked for power at the lights which are supposed to be on when you hit the high beams? I'm not very familiar with that headlight setup. Is it one bulb that has high/low beams and the other just low? Both high/low? Just one of each?

[@movtc6622]

still i dont know whats the point of the relay if i can use fuse and battery ! can anyone explane for me ? can you tell me if i can connect the fuse box for accessories to the car switch ?

[@bwcordes]

mo vtc the big advantage is that you don't have to run a large gauge wire all the way from the battery to the switch and then the load.

[@movtc6622]

thanks for that but can you make video to add fuse box for the accessories when i turn the car on the fuse box will be on can you ?

[@lloydtucker]

Most cars even older cars have a headlight relay The purpose of a relay is two fold 1 to protect the switch which cannot carry the load of the headlights directly 2 provide direct battery current and voltage to the lights For some reason the factory setup doesn’t always offer the same result in brightness I always use the factory wiring to connect to the new relays makes returning to stock simpler, this way the switch side is covered by the original fuse and the new load side is protected with new fuses added between relay and headlight

[@EPEREZ-xk8ri]

Thanks for an informative video, learned alot from it.

[@bwcordes]

Glad it helped you out E.Perez. I appreciate the view and the comment!

[@jasonsvestka9305]

hey have 95 buick skylark no headlights have high beams when hold switch need help

[@bwcordes]

I would be thinking headlight switch, but I would get out your mulitmeter and ensure that you aren't getting power at your headlamp connector when the low beams are on. If not, and you haven't blown a fuse, I would highly suspect the switch.

[@jrbass62]

This is a problem on Suzuki V Stroms. It also saves your starter switch from burning out, The lights go thru starter button!

[@bwcordes]

Wow. That's interesting. I be there's nothing like push starting your bike on the way home in the dark with no headlights.

[@Norwegian_Auto]

Anyone that can help me? I got a Audi A6 avant 2001, wired up a ledbar with the relay getting signal from original high beam. Everything works fine when I turn on the high beam, but when I turn them off, the original light turn off like normal, but the led bar has a 1-2 second delay before it turns off... Any idea of what it could be? I tried with two different relays and still the same problem, and the ledbar I have tested on my other car, and it works fine

[@bwcordes]

Could it be capacitance built up in the light which it's running off of for that second or so? I've seen that with other LEDs.

[@Norwegian_Auto]

@@bwcordes only thing is that when I tried it on my other car there was no delay, and I would assume there is none since it's a high end led bar

[@bwcordes]

@@Norwegian_Auto That's weird. I would probably test the relay manually and see if it is sticking closed. That seems unlikely, but I guess it could be happening.

[@Norwegian_Auto]

@@bwcordes I've already tested the relay :/ and works like a charm

[@bwcordes]

@@Norwegian_Auto Interesting. I can only imagine it's capacitance building up and then being discharged. If you tested the right part of the circuit, you should be able to see resistance increasing over time. It would probably be easier to contact the manufacturer at this point I would guess.

[@Ottonic6]

I know I could look in my service manual. but do you think a 1989 Celica GT has relayed headlights? Probably not eh?

[@bwcordes]

I would think not.

[@pedromuniz9826]

can you use those remotely like wireless

[@bwcordes]

I'm not aware of anyone who makes a wireless relay for an application like this. I'm guessing they would be cost prohibitive for most people.

[@Emilthehun]

Awesome video. But with you talked about what/why relay goes bad!

[@bwcordes]

Thanks for the view. I should try to find a couple bad relays and take them apart for a video. In my experience, it's usually corrosion that kills them.

[@Emilthehun]

bwcordes hahaha you can ALWAYS make more videos!

[@pushpanathantharumalingam699]

Superb 👌 well explain. Thanks bro.

[@bwcordes]

Thanks for the view and comment. I'm glad it helped.

[@juanabreu5127]

Nice video, keep going we need you.

[@bwcordes]

+Juan Abreu Thanks for the kind words Juan. I'm glad you liked the video.

[@enochmendez5806]

I have four roof fog lights can I run all the positive reds together to 87 with one relay or do I need 4 relays for each one ? some one help!!!!!!

[@bwcordes]

+Enoch Mendez You need to look at the amperage of your lights, and compare that to the gauge of wire you want to use along with the current rating of your relay.

[@enochmendez5806]

+bwcordes KC HiLiTES/6 in. 100 Watt clear lens chrome finish Daylighter round halogen flood light

[@enochmendez5806]

+bwcordes. This is the link of lights m.autozone.com/exterior-lighting/flood-light/kc-hilites-6-in-100-watt-clear-lens-chrome-finish-daylighter-round-halogen-flood-light/437375_0_0/?location=

[@bwcordes]

+Enoch Mendez Assuming that you're using a 40A rated relay, I would feel pretty comfortable using it to power all the lights. I am one to push it a bit though and you won't leave a ton of head room when running the lights at lower voltages. An EE would probably suggest two of them. I have no idea how much wire you need to use, but I would look at the distance you have to run them and make sure that you're using the appropriate gauge wire given the length of wire. You can calculate your voltage drop and see recommended wire size for your amperage at the following site which I quickly googled. www.powerstream.com/Wire_Size.htm

[@enochmendez5806]

+bwcordes. I have two 40 amp relays an also have 12v 35 ft wire for each light an for the switch to run back to the relay

[@stephenmodesto-cuyong2340]

sir you can be explain the auto wiring neutral

[@bwcordes]

There isn't a neutral for DC wiring like there is in a house. It's just power and ground.

[@michaelhulsey3150]

I have a 01 dodge ram 1500 I replaced multifunction switch and still have no high beams

[@bwcordes]

I would check for power at the lights to ensure you didn't blow them out somehow (crazier things have happened). If no power there, I would start at the switch and move toward the lights, checking for power as you go.

[@jeetenderkakkar7570]

hello sir how to make headlight relay with microcontrller

[@bwcordes]

That shouldn't be too hard to do. I have thought about controlling one with an arduino and a photo resistor. Just double check that the current your relay draws is less than what your micro controller can supply or get a board designed to control relays and you should be all set.

[@jeetenderkakkar7570]

@@bwcordes How to make missile to kill indian army

[@chrisunknown8294]

I'm sorry did you say the 87a and 87 are the same also just for clarification larger gauge wire is needed for higher voltages not higher amps.

[@bwcordes]

87a and 87 are two different terminals. One is normally open, and the other normally closed. If larger gauge wire were only needed for higher voltage, then there wouldn't be so many large gauge wires on a 12v system in places which pull high current. I'd hate to see someone attempt to run 22ga wire to their starter. That wouldn't take long to burn up.

[@chrisunknown8294]

So larger diameter wire is required for high amps and 87 and 87 a are the two posts that are activated in Deactivated based on magnetic field.

[@bwcordes]

You got it. IIRC 87a is normally closed.

[@bwcordes]

How is the quality on those kits? I usually try to spring for decent wire so I haven't tried the HF stuff because I haven't seen any feedback on it. Thanks for all the posts and insight BTW.

[@Spearfisher1970]

Is there a brand and model on those relays?

[@bwcordes]

I'm pretty sure they are Hella relays. I'll be in the garage tomorrow so I'll try to have a look at them.

[@Spearfisher1970]

bwcordes Wow, that was a fast response. Thank you, and thank you for the video. This is a soon-to-do project on my Jeep Wrangler.

[@bwcordes]

Thanks. These are actually Tyco relays. IIRC they bought out someone and are/were a major supplier of the Bosch style relays. Anyway, the part number is V23234-C0001-X006 It is rated at 12v/30A, but you can use a little math to find out what amp rating you need based on how powerful the lights you'll use are. Hope this helps.

[@Spearfisher1970]

bwcordes It helps a ton. I'll be ordering two shortly. Apparently the word is that the quality of the relays out there is one of the biggest long-term issues with headlight conversions, so I'm being careful about which I end up using. Thank you, and have a Happy New Year.

[@jetskechers5354]

love it thanks bro!

[@WarPartyFitness]

Thumbs up for the super science graph.

[@bwcordes]

Thanks for the view and thumbs up Big Shane. I appreciate it.

[@Fartingcatfish]

Great video

[@bwcordes]

Thanks for the comment, and the view!

[@alext9067]

5:36 Yes, my Bosch headlight switch in my Saab had been replaced many times because it melted. BTW Bosch is junk. All electrical components in the car failed repeatedly. All were Bosch. And as an added bonus, the cross-ref numbers to replace the Bosch w/ other brands were deleted so that only Bosch could be used and only from a Saab dealer. How *&*() nice.

[@alext9067]

Bruce Kirk You got my point, right? I appreciate the suggestion, but I was really trying to say how shitty Bosch was when I had that car. Has Bosch gotten better? I can't believe how shitty they were. The must have either cut every engineering corner or where just plain ignorant or thought they could get away with putting out crap and the public wouldn't fucking be smart enough to see smoke emanating from the dashboard. One of my headlight switches actually melted while I was driving. I don't trust them anymore. I think they're weasels. Is Lucas still around? You probably know more than I do. Thanks for the comment.

[@boomwithpeter623]

Bosch stuff never failed on me, maybe you were unlucky, i have everything bosch in my car, nothing failed, also that 10y warrinty on battery was nobrainer

[@marcosuarez6720]

To teach electricity it is necessary explain the wiring diagrams with practical wiring of electric accesories they both simultaneously, otherwise it is very difficult to understand.

[@MRGierut013]

Hahaha! That graph! I literally laughed out loud.

[@bwcordes]

I'm glad you liked it. I put a ton of time into that graph as you can tell.

[@MRGierut013]

Correct me if I'm wrong, but you could also use two 87/87a relays, right? Left High Beam(87)/Low Beam(87a), and Right High Beam(87)/Low Beam(87a).

[@bwcordes]

You could, but then either the high or low beams would be on all the time.

[@MRGierut013]

Right, depending on where the headlight switch is wired in. The high/low switch is different from the on/of switch. I'm not trying to start an argument or anything, just thinking out loud.

[@bwcordes]

No worries. You're absolutely right that depending on how you want to wire switches etc. the possibilities are almost endless with what you can do. That's one of the reasons I wanted to make this video. I hope people can learn a little about relays and realize what they can do with them.

[@SupertecRacing]

Great video!

[@bwcordes]

Thanks a ton. I hope it helped.

[@viswanathaniyer2372]

good video

[@bwcordes]

Thanks for the view and the comment Viswanathan.

[@Jdmlsturbo]

😂😂😂 “ There she blows, 156hp, four cylinders of Fury. .... The 1990, Dodge Shadow “

[@bwcordes]

Glad you enjoyed that! I try to keep it light in my videos as much as I can. Thanks for the view and the comment.

[@Jdmlsturbo]

bwcordes question, is it possible for me to, change my stock Highbeam/drl and use a relay. I want to add a 3 wire LeD bulb/connector, then drill a hole into the back of my headlight, and put that led bulb in, so my LED Drl Strip will light up. So basically I have the lowest trim model, and it doesn’t have the led drl strip, well the strip is there, just instead my drl is my highbeam half drl

[@bwcordes]

Does the LED bulb actually mount properly in your housing? If not, I'd be very worried about the aiming of the bulb. Otherwise, I'm sure you could wire it off of a relay to turn things on and off in any way you choose. You may want to look at the relays with the 87 and 87a terminals to switch things. Those can be a big help since one of them is normally open, and they switch so that the other opens when the relay is powered.

[@rudolfhuijs4526]

The video should've been around 7 minutes, tops! Install LED bulbs. Less current, less stress for the electrical system and brighter lights.

[@brendotec7241]

Americans usually over explain things, usually repeating themselves three times.

[@izzymaldonado8935]

good info brotha, I know now new shite! 🤘🌞

[@bwcordes]

Glad you enjoyed the video. Thanks for watching.

[@davionbaker6316]

thanks brow works well

[@bwcordes]

davion baker Glad to hear that it helped!

[@brucekirk5386]

87 can be lowbeam 87a can be high beam?

[@bwcordes]

No. One is normally open, and the other normally closed. if you set it up that way, you'll always have your headlights on.

[@Ottonic6]

so you have a relay for each brightness not for each head light? 1 relay for high beam L & R, and 1 relay for low beam L & R?... I got what you did, but it would have been nice to actually have you show what you did. rather than you tell and point how you did it... Thanks!

[@bwcordes]

That's what I did. I just did a video series which shows in a little more detail how I did the same thing to my Lancer. kzbin.info/www/bejne/bF7Qhmiqp8dlg9k

[@Ottonic6]

bwcordes - Thanks for the quick reply......

[@Brendalo1]

Start at 11 minutes... never mind I wish this was clear

[@panglaotravel385]

Thank you sir

[@MechanicForGMCCars]

Peopel use external diodes those Bosch relays are crap expecialy EU relays all have ic chip controled so internal diodes leak they fail .

[@bwcordes]

I installed some hella relays with internal diodes. They just had the diode soldered in them. They work great.

[@MechanicForGMCCars]

@@bwcordes you see not only GM did fatal mistake but also bosch and delco no diode for delco 12si alternator no diode for positive linear voltage regulator the alternator is bound to 4pin bosch relay on pin 86 and commonly they are ic chip controled no ballast for xenon lights or halogen lights lot common conections for + and - and including multipel relays interact with ich other they behave nearly identical like dual 5 pin relay. My car is Opel Ascona C also knowns as Cavalier or Monza or Cammri . My car nearly has no electronics insted it has 4pin defroster ,3pin blinker,2pin buzzer ,6pin wiper relays ,positive linear voltage regulator and 4pin GM Ignition Module . My deam car acts like Hit and Miss engine ,or refuse to stop or self aceleratea at full trothel such bizzare effects no one ells on the internet didnt witnes unless my self so belive my when I say this make ich circuet sepetate add lot resistors diodes and reverse polarity protection if posibel clossed loop baterry system due to rosting problems use only wires not engine ground!!! US relays might by great and I agree with simpel circuets but Asia EU Australia versions are pure desaster not to mention crazzy Brits who for some reason decided to fummel around pin positions like the 700Y dash regulator . I hade to 5days just redraw wire diagram to understand how this GM wire harnest works it looks like bomb droped in that thing and still didnt figure out loot misteris why my car behaves strange ways some problems I found but some still culd not trace down and thats 40 year old car not modern car and under static I hightly doubht even best computer equpment can help because profesional car electritians culd not fix those problems. So fair advice to use dual baterry systems and cloosed loop voltage regulator for those old delco 12si alternators and replace some shity staff in the proces replacing them with heavy dutty industri parts. Just talking out of experiance those old cars seriusly are great but shiti in design they have lot flaws. Im my self useing plasma and some times high amp ignition so thats why those mentioned circuets need upgrade if not protected or seperate circuets done for exampel on hv ceramic capacitors the starting alternator charge or cutt in current will by delay at around 3-4k rpm. My own diodes failed they are also Bosch and Hella also some use Siemens relays so use extra strong diode and just trust my on this one.

[@jackiechan_wtf4041]

I feel like I'm back in college. lol

[@bwcordes]

***** Thanks! I'm taking that as a huge compliment.

[@pollydor07]

THANKS

[@alstevens44]

So where is the dimmer switch connect

[@bwcordes]

On the chrysler cars the dimmer switch for the interior dash lights is a part of the headlight switch. It does not need any changes. The high beams are controlled on the stalk and send power to either the high or low beams. You don't need to do anything under the dash for the relays to work.

[@nyiluam]

thanks

[@bwcordes]

Thank you for the comment and the view. I hope the video was helpful.

[@Fritsvrolijk]

You are welcome Have a nice day 2

[@papatorr3669]

Why can't the industry standardize red is +, black is - , and green is ground?

[@bwcordes]

I think one of the biggest factors is the fact that you have so many different wires coming off of a common line that all power different things. You need to color code each one of them for identification. Then there's the fact that you have different voltage sources under the hood. There are also different grounds which need to be identified. It would be nice if there was some commonality, but I think there are too many different ways of doing things for everyone to agree.

[@mrkss4552]

Stagger your connections or you'll end up with a rather large lump if you're going to wrap up the wires , looks kinda like a snake swallowing a rat

[@bwcordes]

Great tip. Thanks for the comment and the view!

[@walperstyle]

Subscribed. You sound way less gay than I do in my videos.

[@bwcordes]

Thanks I think?

[@kommonmanz3224]

That literally made me lol!

[@rajbahadur2162]

Nice vidiyo sar

[@jojozepofthejungle2655]

This is just gibberish to me, a drawing is just not the same as seeing it for real. I can pull apart the motor and put it back together yet cannot understand this without being shown.

[@bwcordes]

What part don't you understand. I think I might have a relay in my box that's apart and able to show how it works exactly.

[@jojozepofthejungle2655]

@@bwcordes it's ok I figured it out, I didn't even know what a relay looked like (hit myself) dah. I'm just learning to be a, as you break down, you tube mechanic 🤔 but thankyou anyway.

[@manitsmike7847]

Ding ding