Wiring Products - How to Wire an Automotive Relay

Instructions for wiring a standard automotive relay with descriptions of the pin-out and the schematic. I go over what each contact of the relay is for, and how to understand the schematic that is usually printed on the side of the relay. These relays are commonly found in automotive and low voltage electrical applications. Please visit us at www.wiringproducts.com to see all our automotive electrical products.

[@thewomble]

Nearly gave up trying to find the way to wire a relay till I came across this excellent video. Simple and straightforward. THANKS

[@lh2197]

Short and sweet just like a cheerleaders dress. Straight and to the point. Thanks a million sir

[@kabandajamir9844]

World's best teacher thanks

[@tyler_racing]

Great simple video for those of us who just don’t get electronics! Thanks

[@jellevr88]

Short, descent explanation. Couldnt ask for a better video, I thank you kind sir!

[@doranvee5944]

My wife wanted to add air horn, and you made me look like a hero! Thanks!!

[@RoiratNews]

Great information. Exactly the instructions I was hoping for. Thanks for leaving out the music.

[@josephs9268]

I watched some many videos, went through countless searches for info, and Was still baffled. Watched this video once and I'm absolutely clear on exactly how a relay works, why it's used, and how it's wired. BRAVO MY GOOD SIR MUCH APPRECIATED 👍. Thanks for taking the time to make this video.

[@mr.blackhawk142]

Wass???? Vass iss dass??? :P

[@mr.blackhawk142]

I prefer written info, something I can bring with me to my bike and use for reference. NOBODY took the time to do that, but the verbal instructions were EXCELLENT, and I made a diagram from them!

[@antonybeaufort2308]

Thank you, very useful when you havent done an 12v electrical job for a while!

[@noahbannon7600]

Thanks man. Simple, and to the point

[@firehawk97]

Dead simple explanation, absolutely perfect. Will be using this info to wire up an intercooler pump to a Saturn Ion that I am supercharging.

[@shivandabideen4587]

By far the best explanation on KZbin. Thanks man

[@Mvince2011]

Quick loud and Clear.thanks mate😏

[@cheesemons]

So simple and yet so informative!

[@patrickbradshaw363]

Thank you so much this was such a helpful video, now i know how I can bypass the broken relay on my car.

[@AztecWarrior69]

If you want to remember the pins on a Bosch style SPDT relay like this, you can remember this: Victory Comes Now = Voltage+ Common Negative. Add simple Open Close. So "Victory Comes Now Open Closed". Read left to right top to bottom. It's already a part of people's knowledge base as an almost or modified the "sign of the cross". You can even say it : "Valiant Victory Comes Now, Heaven is Open Hell is Closed" = Verticals Voltage+ Common Negative, Horizontal Open Horizontal Closed.

[@sccarzonesccarzone5582]

Most helpful video ever! Litterally just what you need to know to use it, id been educated on it before and forgot witch pin goes to what. This video was perfect!

[@shaileshbilwal1093]

Relay athletik

[@comesthru]

Clear explanation, for a techie, you are pretty good.

[@samuelmaigwa8480]

Straight to the point....

[@voidhawkflashlights2161]

and the cheap ebay relay actually functions now! China harness as follows: Black = positive power in,,,, Yellow = ground,,, white = switch energy pos,,, Red= energize switch on,,, Blue = energize switch off. Thank you for making life easier!

[@jeffreynelson2660]

Thanks for the very clear explanation, you saved me from making some mistakes.

[@jorgespartan1978]

Great video very clear and simple. Congrats!

[@DanielHalus]

i did understand from the first time, but i did watched again because is a great video. thx

[@stevenstranz699]

Completely lost but now aware and found. Thx

[@electriciandallastx9182]

Thanks for the strategies you have provided here.

[@vextrek6036]

Good video. Thank you.

[@flipztuh24]

I love your video, very simple and easy to understand 👍

[@NorfolkN]

Thank you for this brilliant video

[@gerardomontano9875]

Best explanation quick and simple

[@MrBchott]

Perfect explanation thank you

[@gordenfraxby84]

Great explanation thanks! :D

[@erictownsend8711]

Nice and simple. Thanks.

[@augustuscesarcabrera3673]

Very helpful men, Thanks!

[@Electronzap]

Good info.

[@alexandru_mateescu]

Thank you!

[@catalinadude6218]

Perfect. Thanks!

[@oldstar1952]

Right on, could not have been better explained

[@smallgoon]

Easy to understand .. thanks

[@motorcyclepimp]

Thanks! works perfect.

[@johndrane524]

Thank you sir, for the great instructions!

[@gerardog2663]

Is it OK (not critical and relay will still work) if 85 and 86 are connected with the polarity inverted?

[@gwats19577]

I used the inside terminal (87A), and was wondering why my fog light switch was working backwards..... thanks for clearing that up!!!

[@ved8315]

thanks for explaination

[@sylar1717]

Thanku. Nice and simple.

[@timothyadonis4970]

Great video 👍👍👍👍👍

[@candybisht9953]

Osm such a simple explanation..

[@ShawnTRD]

Good thing I watched this.

[@MIC-LS]

The Simplest way is always the best for me.

[@oscargonzalez3783]

Hey I like you channel lol have you used this setup on the s10

[@MIC-LS]

@@oscargonzalez3783 chevy S10 y GMC sonoma they are both the same 1995 Sonoma is the same as an S10. Mismo perro diferente collar.

[@lexsoft3969]

I know this can be the standard for relay wiring. But I have seen different wiring such as the following : - terminal 85 is used for input from trigger device (switch, etc), whereas 86 to the ground - terminal 87 is used for input from battery through fuse - terminal 30 is used for output to the load (headlights, etc) which seems acceptable, though I am not certain for safety, etc. I prefer to choose the method shown in this video, because it is more DIN 72552 compliant, esp for terminal 85-86.

[@thadwayneferrwalt147]

Hi. I understand your video when I'm only powering two 12v devices, e.g. camera and audio headunit. But what if I have three? Rear camera, audio headunit, and a underseat active speaker.

[@jonathanalvarez8952]

Could you make a video on how to wire two relays for door locks actuators. For possitive and negative. Thank you and great video vary thero and nice quality picture

[@guillaumeZR]

Best video

[@tmendez31]

So the first terminal is your common? And the next two are your normally open and normally closed contacts? And the last two are your negative and positive contacts that trigger the relay? I heard trigger and ground rather than positive and negative. I didn't hear the voltage requirement but I'm assuming 12 volts. Gotcha.

[@mattmgarza]

Are these the type of relays I need for wiring a remote start? I know a few of the wires are 500 ma and a few are 200 ma.

[@3nginuur]

How would you wire a relay for a remote start to where it will cut the power to the remote start when you press the break and switch power to the main so the car keeps running? also how can you make a relay so ground negative is only on when the remote start is on, normally there is a "ground when on" wire but for some reason my unit is without one.... so I figured I can manually make one? Thanks

[@nicskeptic]

What do you hook the other side of switch to??? Constant +

[@Fritsvrolijk]

Thanks super

[@ashqelon7267]

This also includes the same similar function of the NAPA PN 735-0078 that has only 4 connections. Just no 87A point to concern about.

[@sunnyr8434]

Should the relay be located near the battery or near the load/device or near the switch,?

[@8DC_VR_Avatar_Infinite.678]

How would I use a relay to control 4 cams in my car using a i-beam cam switcher and a switch

[@craphittingthefan9445]

Hi, my instructions don't say the same as what your showing. pin 30 shows going to the devise being used and pin 87 is where the power off battery goes with a fuse between them or does this matter? I did hook it up to my fuel pump according to my directions and it seems to be working just fine, I did however use 10ga wire being its a fuel pump located in the rear of the car?

[@wiringproducts]

Because it is basically a switch, it will work if power is connected to terminal 87 and your accessory is connected to terminal 30. However, if you have a terminal 87a, then terminal 87a will no longer have a function since it will be connected to your accessory, not the power when the relay is in a non-energized state.

[@craphittingthefan9445]

Thanks, I am not using 87a so I guess this will work for me.

[@Duwop77]

Wiring Products Thanks great vid. Very simple and straight to the point 👍

[@feedbrain6257]

Thank you, what to do do with numbered 1 2 3 4 5 instead, Ford always this numbering type. thx again

[@michaeltempsch5282]

Judging by pics of Ford relays on Amazon; 1 & 2 should be the coil (can't make out which is supposed to be +12/ground), 3 the common switch terminal, 4 the normally closed switch terminal, and 5 the normally open switch terminal.

[@robpeterson4742]

How to read relay type voltage if you want order and replace.

[@brunoburtoni8479]

A relay needed for each accessory horn lights??

[@Colopathe]

Can you wire the same device on the 87 and 87a and still have it to switch off with the 87a ?

[@jimjensen1096]

Not really. Power goes to 87 when switched on, right? When switched off power leaves 87, going now to 87a instead. If you were thinking to run the ground for your device to 87a it won't work. Ground your device to the common ground(frame?). You could run another device from 87a, also ground to frame, but your switch will be in the off position. Clear as mud, right?

[@stealhty1]

On the triggering Spades there is a Damper Diode

[@rajankn1873]

Hi I have bought 12v 30 amp harness relay from online. I have installed as per the directions but the connected LEDs have not blown. The battery is 12v 20amp. Is there any concerns with amp of the product & battery

[@michaeltempsch5282]

The battery is likely 20Ah (campers hours) which is how much capacity it has (like gallons in a tank). 30A of the relay/harness is how much current (flow) it can handle. Capacity if not the same as flow. 10A running for 2 hours makes 20Ah of capacity used. If the leds are designed for automitive/12V use, they will only draw as much current as they need, no matter how much the battery can deliver (likely 100s of amperes for brief periods) or the crest of the components are rated for...

[@arcanum3010]

Excellent explanation. So,how come,on some wiring diagrams,the battery source wire goes to 87?

[@wiringproducts]

You would connect the battery source to terminal 87 ONLY if you want to use the relay to turn on a device, such as a fan, and are concerned about there being voltage on terminal 87a, when the relay is turned off. (you can also put a piece of electrical tape over 87a to insulate it if it is exposed). However, when the battery source is connected to terminal 87, the relay will not work as a change-over relay (change the voltage from terminal 87a to 87).

[@matthewlett3858]

I need to no what wires to run to be able to set up my 30 sec timer relay not sure how

[@akhilhari9676]

How fix the...pin marking with A,B,C,D,E can't understand

[@Djmambo77]

hi. @ 1:29 you mentioned that the trigger will attach to one side of the coil, and the ground will attach to the other side of the coil. Does it matter to which number the trigger/or ground are attached? per say, can I attach either the remote or the ground to 85 or 86, as long as the other is on the opposite side? thanks for any info.

[@michaeltempsch5282]

Often it doesn't matter, but if the relay has an internal clamping/free-wheeling diode, it needs to be hooked up the right way, so as to not conduct when power is applied to the coil (it should only conduct when the coil is de-energized and the collapsing magnetic field induces a reverse voltage spike). If not, it's likely that the diode and/or upstream fuse on the control line will blow

[@Djmambo77]

@@michaeltempsch5282 Thanks for the quick reply. I also see some videos here, from some very respected installers, saying that the Batt +12v goes on 87, and the accesories on 30. wao confusing. can that be done as well? not being a pain, Just that I've already hooked my relays up, finding out before powering it up. again, thanks for the info

[@michaeltempsch5282]

@@Djmambo77 30, 87 and 87a Are the 3 terminals of a double throw (changeover) switch. At rest 30 and 87a are connected, when activated instead 30 and 87 are connected and 87a/30 disconnected. If there is no 87a terminal (not all relays have them - cheaper to make w/o), then it's simply 30 to 87 when activated, no connection when not activated. So for the feed and load, 87 and 30 are interchangeable unless you wish to utilize the changeover function of a relay with both 87 and 87a terminals.

[@Djmambo77]

@@michaeltempsch5282 Thank you very much for helping explain

[@InfinitechIT]

I've been trying to make my 12v power outlets turn off when I turn my car off. Could I use a relay like this and put it under the dash? And could I use the power for my stereo? Example: connect fused source to #30 and then run a wire from #87 to the power outlet. Then connect fused source for the stereo to one side and connect the stereo power wire to the other side.

[@gsbacorn]

Mike Walker No it won't work like that. the 85 and 86 terminals are to "flip the switch" inside of the relay from 87a to 87 and vise versa. They would need to be switched power and ground to them.

[@InfinitechIT]

Thank you for your reply, I was able to figure it out and have it all working now. I used the existing power to power the outlets through the relay and I used an add-a-fuse in the radio fuse slot to control the relays.

[@miguelzepeda20]

it's easy once you get the hang of it

[@gwats19577]

Looks easy enough......

[@vahhone]

How fo you determine the size of fuze?

[@mikegay8738]

Can I activate the relay with a ground instead of power? And I really don't understand the 87a terminal? Would you run that wire also to the device that you want to power?

[@wandahelmer1038]

Mike Gay when I wire my relays I use the ground to my switch that way I only run a ground thru the fire wall other wise yes you c as n switch using the ground

[@lenwhite9901]

Answer to your question about 87a. My understanding is that is used when you want the relay to turn something off. For example, you would have a low oil level signal going to 87a so it will shut off your ignition if your oil pressure drops. Probably lots of other examples, but that is how a friend uses a shut off relay in his race car.

[@hellohai2693]

Tq

[@shaikhnawed5036]

What's the cost of relay

[@adrianolavarria3362]

Simple

[@lorddunsany6674]

Awesome, would be more awesome with the nail lady.

[@2460speedy]

85 is the ground. 86 is the trigger. 87 goes to the lights etc. 30 in the power input.

[@JP-fr5zq]

Can I wire a switch on 87?

[@ExodusisThere]

Realistically you would wire a switch to the power of the relay

[@charlesdickens6706]

...my five pins are in different places . I'll simply open up the relay to eyeball the connections .

[@ved8315]

thanks for explaination