Honda Cooling Fan Circuit Troubleshooting and Cooling Fan Switch Replacement 2000 Civic

[@BigDog50001]

*Tools and Parts* This channel earns a small commission using some of these links - at no additional cost to you. PowerProbe IV: amzn.to/2MVso7d Lisle Spill Free Funnel: amzn.to/2LiJrOU OTC 3636 Test Light: amzn.to/2zM5cjx Genuine Honda Cooling Fan Switch: amzn.to/2Lpn2hv Tekton Sockets: amzn.to/2Lhhd6N GearWrench Ratchets: amzn.to/2MVsHin GearWrench Flex Ratchets: amzn.to/2zPkwM0 The Big Dog 50001 Automotive Channel Store can be found here: www.amazon.com/shop/bigdog50001automotive

[@billymaravelias340]

1⁶

[@undrgroundperformance]

Thanks alot🙏🏼.

[@gypsychristo6727]

Thank you so much. This video helped me more than you know. I'm a single mom and can't always afford to have a mechanic fix my car. You broke everything down so that I could easily understand and I was able to diagnose the problem myself. Thank you so much.

[@BigDog50001]

Awesome! Thanks for the comment!

[@jasenleidle1986]

Agreed.This guy and his channel is great!

[@ozb2006]

ok, not the car i have, i have a 2000 accord v6, but you are the first person who explained the cooling circuit so well that i didn't need the rest of the video but i have watched it anyway to give you the watch time, good video, hopefully its the same circuit on the v6, if so i'll make a video for to to troubleshoot this problem on the v6 i am not the best troubleshooting mechanic in the world but youtube does not have a video about how to find this problem on the v6 accord, thank you for making this video i hope this info will help me to help others

[@4theRun]

Thank you so much for this excellent video. It helped me fix my '99 Honda Civic easily. I let my old man use it who's experiencing some cognitive decline. He was a great mechanic in his day, but now he can't figure out why he can't figure stuff out anymore. With the help of the Chilton manual and your video I was able to diagnose the defective fan switch very quickly and easily and I got him back on the road. God bless you!

[@droidaimone]

Jesus this is so clear. Watched 10 videos claiming to help diagnose if fan is bad or switches. Thank you.

[@BigDog50001]

Glad it helped, thanks for the comment!

[@clinthoover9135]

Hands down the best “How to” video on KZbin!!! I love the schematic, plain explanation of how it works and how to troubleshoot and repair!!! Thank you for your time and effort in making this video. Keep it up good sir!!!

[@BigDog50001]

I appreciate the comment, thanks!

[@jopaul93]

0000000000000000000000000000000000000000000000000000000000000000000000000000

[@kennethmcclure3305]

Saved me putting in override switches for my fan. Finally, somebody that makes something difficult, easy!

[@BigDog50001]

Glad it helped, thanks for the comment!

[@LarryMFjohnson]

Dude!!! @19:03 you explained my exact problem!! But unfortunately I had to replace 4 parts and 2 radiator flushes until we realized that air pocket was in there and it needed to purge!! Ahh man, what a headache it was. I replaced the thermostat, cooling fan switch, fan relay, upper & lower inlet valve hoses, and the engine cooling temp sensor. People need to know how important it is to allow the radiator to burp out that air as well as allowing it to purge with proper amount of coolant.. I wish I had seen this video 3 days ago! Great job explaining everything man, thanks!

[@BigDog50001]

👍

[@grenginator]

Fantastic walkthrough. I've never been fully satisfied with a youtube walkthrough before now. Thank you for this!!!

[@BigDog50001]

I appreciate the comment, thanks!

[@steveweatherford1]

I can fix pretty much anything mechanical. But I’m a Dilroy when it comes to electrical. I can figure out simple positive and negative. But you put it in a very easy format to understand thank you very much . As soon as you told me where the switch was I knew what to do. But I still love seeing the diagram in layman’s terms

[@BigDog50001]

👍

[@DavidCoffill]

No shortage of problems with this vehicle! Great to know it is in good hands.

[@BigDog50001]

Thanks!

[@tjames22123]

Yep, the fan switch was the culprit. I had a hunch that was it all along. I followed all your diagnosis steps. Brilliant!!

[@BigDog50001]

👍

[@jesselepe1130]

Broke it down and explained it beautifully

[@BigDog50001]

Thank you, I appreciate the comment!

[@robswrenches9501]

Thanks for the refresher course on a basic cooling circuit. Good diagram and great explanation of how relays work, not to mention isolating parts of the circuit to detect any suspected issue. 👍👍👍👍👍

[@BigDog50001]

Thank you Rob!

[@fotomedia1]

Great video. You pretty much covered it all for the cooling fan issues. This saves me from viewing 10 other incomplete videos.

[@BigDog50001]

Thank you for the comment, I appreciate it!

[@joseeone77]

Great video. I think this will help me solve my fan issues. I have checked all components ( fuses, relays including continuity, swapped out etc sensor and still no power to fans. Not even when a/c is turned on. So I think the next step is check grounds. Great video, very informative. Thanks

[@BigDog50001]

Thanks for the comment!

[@amasoak47]

same issue on a 95 accord v4. Have you fixed the issue? what was faulty?

[@tmst2199]

Wow! Someone who can describe an electrical diagram! You 'da man!

[@BigDog50001]

Thanks 👍!

[@Ottonic6]

Excellent! Great diagnosis. I almost commented to make sure you check your power from the relay to the switch, but you got to that... Thanks!

[@Ottonic6]

Also, even though it might cost a little more, get OEM replacement parts (Duh). You'll be better off in the long run..

[@BigDog50001]

Thank you for the comment and the input!

[@josearana19]

Lately we been having extremely hot Weather forecast in Los Angeles,. My cooling fan was taking too long to kick in,. I watched your video,. Very good info,. Thanks for the Hints

[@mannyclemente7159]

Thanks for the paper clip trick brotha, saved me a couple hundred bucks! I changed the thermostat, but in the end it was the fan switch. 👍

[@BigDog50001]

Glad it helped!

[@danielhillwick8430]

This is the first video I have seen by you. Great video well presented and easy to understand. I like the white board drawings

[@BigDog50001]

Thank you, I appreciate the comment!

[@pedrodomingues9381]

Thank you for your share. The explanation regarding the wiring diagram was simple enough to make me think "Can I close the circuit and test it from the relay?". Soon after, I saw how you test the cabling and did it to mine. Same result. ECT sensor is giving readings however not starting the fan which I tested earlier directly to the battery. The Haynes manual only refers to continuity with a Multimeter. Below 90ºC shouldn't give continuity. Between 90ºC-95ºC should. A paper clip sorted it out :D

[@BigDog50001]

👍

[@TheOverpricedcoffee]

Thank you for specifying how the fan and AC fan work on the different cooling system setups

[@BigDog50001]

No problem 👍

[@jimmymixon117]

Big Dog, thanks for your help with cooling system for Honda's and I look forward to seeing more of your videos. Also, thanks for making them dummy proof. If you can't understand what you are talking about, then you don't need to be working on cars.

[@slideo12]

Your the best! I used the paper clip trick and it helped me figure out the issue quickly!

[@tsgtownsend]

Thanks! I'm going to check the switch terminal tomorrow. I replaced a bad relay, but the cooling fans still do not come on. So, hopefully I will have the car fixed by the weekend.

[@BigDog50001]

Thanks for the comment!

[@DANNYN224]

Omg thanks for the video now i can fix my overheating issue my cooling fan was not kicking in only ac fan ik honda both are suppose to do it together or independently thanks you so much you are a grace of god

[@BigDog50001]

I'm glad it helped, thanks for the comment!

[@northstar875]

Fantastic video. Almost replaced my head gasket because It was overheating. It was the fan the whole time. Doh!

[@BigDog50001]

👍

[@BigDog50001]

There is confusion on torque specs due to Honda calling everything an ECT (Engine Coolant Temperature) in the service manual (see torque specs below). Even I quoted the torque spec wrong in the video (I generally do not use a 1/2 " torque wrench, or an adapter to a smaller torque wrench, on anything under 20 lb ft). Torque Specs: For D16Y5, D16Y7, D16Y8, B16A2 engines: ECT Gauge Sending Unit: 7 lb ft Engine Coolant Temperature (ECT) SENSOR: 13 lb ft Cooling Fan Switch (also called ECT Switch): 17 lb ft (part replaced in video)

[@queenminks28xd64]

Thanks, you made it easy to understand.

[@mounir2312]

Thanks for the Great video! I did the same what you showed, I bypassed the fan switch censor with paper clip and the fans started working. I changed the fan switch censor but the fans are still not working. I bleed the coolant but no luck yet. Thank you!

[@BigDog50001]

Make sure terminal pins at connection are good, coolant bled and that coolant is actually reaching 200 degrees (otherwise switch will not close). Aftermarket switches are typically not as reliable as Honda switches. Thanks for the comment!

[@lolobon1331]

Best video out here with explanation so detailed! You are the best man thank you! 🙏🏽

[@cmorea]

Great Vid. I heard a sound at 24:48 that I've been hearing from the drive belt area on my '90 Accord for the past few years. I changed the water pump and timing belt and it hasn't gone away. I only hear it when the engine is warm and the car is not moving or moving very slowly.

[@agarciaagarcia3598]

Most excellent video. Lamens wiring explanation was nice as well.

[@BigDog50001]

I appreciate the comment, thanks!

[@gdroc94]

Thanks. I had replaced the fan itself but forgot about the fuse!

[@BigDog50001]

👍

[@sonjadickey913]

would same principals apply for 06 Pilot Ex? passenger side fan won't kick in even after replacing it. Having hard time finding sensor wiring diagrams. Any help/suggestions would be greatly appreciated!

[@emrahhakki4616]

This guy knows his shit Well explained man good video 10/10 for me 👍

[@BigDog50001]

I appreciate the comment, thanks!

[@robertwhatley9078]

Big thumbs up man I am having that exact issue with my 2003 Civic. Thank you so much for this video, it is much appreciated.

[@BigDog50001]

No problem 👍

[@rockalliance8815]

Hello thanks for the upload it’s been helpful. Have a quick question, I checked everything over and was doing the test the car was running and I turned on the AC and it stalled. It Hasn’t started since the test. Any ideas what happened? All relays and fuses are good, new Heater core, fan is good. I’m lost

[@scottst.vincent6964]

Thanks for the video. Just helped my son solve his 2000 Civic problem with this.

[@BigDog50001]

Good to hear, thank you for the comment!

[@reaper78541]

Came here at your suggestion. Its on my to-do list for tomorrow. Thank you again.

[@BigDog50001]

Hopefully the videos on this Civic help you out! Good luck with the repairs.

[@reaper78541]

Thank you so much.

[@eddiemanuel3946]

This video helped me how to resolve a problem with my car thank you for your experience and knowledge !!! 👍🎥

[@williamhaines856]

u r anexcellant teacher im impressed common sense thank u

[@massimocedillos1123]

Finally a well explained and helpfull video. Ive been looking at videos forever and could never find a good one until now. Thanks for the help!

[@BigDog50001]

Glad it helped, thanks for the comment!

[@ronethridge9875]

thanks for the knowledge on honda cars/yeap you right-like your profestional /thanks much

[@kevinzuniga1723]

You Kept it nice and simple, I just fixed this outside of autozone lol No more overheating!! 🙏🏼🙏🏼 Thank you !

[@BigDog50001]

👍

[@tmst2199]

Be aware that an aftermarket switch may take a premature crap.

[@jashuagonzalez7671]

2020 & still useful just helped me out thanks a ton

[@BigDog50001]

Glad it helped!

[@Eirocina]

@@BigDog50001 thx for the vid. normally i just meh but this kind of vid is helpful. thx again.

[@nickwilmore9314]

EXTREMELY helpful! Thank you

[@richardfittzwelllll231]

Thank you.... saved me money and time just low coolant.

[@BigDog50001]

👍

[@mrciscoramirez]

Excellent video! Helped me understand a lot , you explained every step , much appreciated

[@wailingmongi]

Great video pal. Have you ever thought about making the dashboard temperature failure guide?

[@anupjthomas]

Thank you, great DIY diagnostic process!

[@BigDog50001]

I appreciate the comment, thanks!

[@MichelAugustin-h7w]

Thank you for that video. In a case where the fan is working once ignition on engine off, what would be the cause? Relay is okay(if I remove the relay, fan stop working when ignition on), temperature switch is okay.

[@BigDog50001]

Depends on the vehicle, but most Hondas have fans that can be turned on by the engine control module (ECM), if ECM sees too high of an engine temp on Engine Coolant Temperature Sensor (ECT) then it will turn on fans even if vehicle is turned off. A bad relay (stuck on) can keep the fan on also. I would probably start by verifying that the ECT that the engine computer is using (not the temp sending unit for gauge cluster that some models use) is working properly and that the relay(s) for the fan(s) are also working properly. Thanks for the comment!

[@jonathanzepeda6048]

hey man. so when watching this video, i first used the paper clip method to see if the entire circuit was working and indeed the fan did come on. every time without a doubt. my first course of action was to change fan switch sensor or whatever its called. that didn't fix the job. i made sure the system was properly bleed and no air pockets were in the system. i even changed out the fan, and the coolant temperature sensor. nothing. the fan still doesn't come on? is it possible regardless of the entire circuit working when a paper clip presses those tabs there could still be a shortage somewhere? please get back to me thanks!

[@BigDog50001]

If fans turn on and run without issue with paperclip then the rest of circuit integrity is fine, the issue is most likely limited to the switch area itself or coolant. Some things I would think about: 1. Bad switch/crappy aftermarket switch 2. Air in coolant system near switch causing false reading (these models can be difficult to bleed without a spill free funnel) 3. coolant not reaching approx 200 degrees so switch not closing (system ok/too cold outside) 4. coolant not reaching approx 200 degrees so switch not closing (bad thermostat/crappy aftermarket) 5. bad contacts at switch connection (loose/corroded/bent/spread terminals etc)

[@mavargas8701]

Awesome video I appreciate you sharing your knowledge, was all the work done with the car battery plugged in?

[@BigDog50001]

Yes battery was connected, the checks done needed it to be connected. Thanks for the comment!

[@thehgsiv3869]

Thanks for the very informative video. It's too bad that the warning about the paper clip came at the end because I think that may be my problem. I followed all the steps while watching (my bad for not watching all the way through first) and replaced the switch with a new one from the auto part store and the fan won't come on, except with the paper clip. So my guess is either the switch doesn't want to play nice since it's not a genuine Honda part, or I damaged the connection with the paper clip. Is the connector changeable? Or should I get another part from Honda? (Would the auto part store take the part back??) Any advice on what to try first? Thanks!

[@BigDog50001]

I don't think you can get a new connector for just that part (but I may be wrong), but a used one from junk yard is a possibility (just cut and splice). I would look inside at the connectors and see if they are bent or damaged, many times they can be corrected/straightened with a small pick or something like that. If the fan comes on consistently when jumping with a paperclip then the issue is most likely isolated to that area (Bad fan switch, bad connector(s)/connections at fan switch, air in cooling system near switch, vehicle coolant not getting hot enough to close switch, etc). Thanks for the comment!

[@thehgsiv3869]

thanks for the advice. i will give it a try! cheers

[@delltek102]

checked motor blower/fan is good, cold switching and warm switching works I can feel it air changing temperature next to the fan...but the air is still not blowing from the fans - 2010 honda crv ex

[@Archibald_h]

Thank you for the video. Really awesome job explaining.

[@BigDog50001]

I appreciate the comment, thanks!

[@balla4life2369]

Awesome video! Informed me exactly what I need to do. My only question is could a bad thermostat be also cause the switch no to work correctly?

[@BigDog50001]

Balla4Life2369 Thanks! Yes, a bad thermostat can stop the coolant from getting to 200 degrees which would stop the switch from closing.

[@nativepower1665]

U are one damn good teacher u have it. Thank u, my Honda put me through schoo. Love my honda 👍

[@BigDog50001]

I appreciate the comment, thank you!

[@pab10100]

Thank you Sr. Very helpful you save me a bunch of money on the mechanic shop.

[@BigDog50001]

Thanks for the comment, I appreciate it!

[@shanz3n5]

great video, very articulate with all description and troubleshooting technique. thank you. This should be very similar for a my 1999 i expect. If all testing in this video is good and im still running hot......(The temp gauge was pegging H...just a hair below redline, so flushed coolant and replaced thermostat). Still gets too Hot...... i will replace the radiator cap.... I have only been able to lower temp by turning on heater blower motor. QWSTN - I see no signs of leaking coolant, over flow level is now hi and radiator is low, I dont see exhaust steam, should i be looking at water pump?

[@Jo34457]

Hi I replace a new thermal temperature sensor . I try use the paper clip as you stated at that connector but my fan won’t turn on . Please help

[@thandozililo7905]

Thanks Big Dod, I'm having the same issue on my Honda ballad, iwil do all you have taught me. God bless. #SouthAfrica

[@BigDog50001]

👍

[@osomayor7083]

Thanks for you video I have one question my civic 2002 when the fan coolant turn on the fan for the ac turn on to.. when stop the fan for the coolant both fan turn off, the ac I turn on but the fan for the condenser not turn on..

[@BigDog50001]

That is probably going to need some troubleshooting done and it is a little bit different setup than the vehicle in this video. Both fans should turn on together on those Civics (control side of the relays are wired together). The fans can either be turned on by the fan switch when coolant gets to around 200 degrees or they can be turned on by the engine control module (ECM) when it received an input signal from the A/C system. It may just be an intermittent problem with the A/C condenser relay and you just happened to see it fail when the A/C was turned on. If the A/C system is not working, then the A/C system is most likely the issue and will need troubleshooting.

[@osomayor7083]

Big Dog50001 Automotive thanks to respond quickly...

[@mubarikhussain5988]

Thanks, this helps me to fix the fan switch issue 👍

[@BigDog50001]

👍

[@seanhunty9304]

I have a 2003 Honda element . The ac quit the other day. Still takes a load on the engine, still blows air. My 30 amp condenser fan Under the hood was blown… Changed it and the ac condenser fan came on. Thought all was good. Went to turn it on next day, load on ac , warm Air again, ac fan not blowing . Fuse blown again. U have any ideas by chance? I think it could be the fan but not sure 🤦

[@masumbhamji7707]

Very nice explained. Well done.

[@BigDog50001]

Thank you, I appreciate the comment!

[@nicomorales23]

Would this same procedure be good for when the radiator fan stays on after turning off?

[@manuel9044724]

Thanks for your support

[@BigDog50001]

👍

[@jeredjaramillo]

Great video! Could the relay be bad and constantly closed all the time making the fan run from start of vehicle til shutdown of vehicle?

[@BigDog50001]

Voltage (Power) to the fans are typically hot all the time (not run through the ignition switch), so if a relay was stuck closed the fan would run all the time including when the key was out of vehicle. Although not a huge player in controlling fan operation on this model, the Engine Control Module (ECM) can activate the radiator fan and cause what you are describing.

[@Secretdawg925]

Watching this video made me realize that ive watcged this video before didnt have a 24mm socket and stuck a paperclip in there and drove like that New Honda same problem and I can't believe I forgot I can test the ground like that 😊

[@dennyodea6945]

I have a 2002 civic that the fans are turning off every minute or so for about 6-8 seconds then back on I have replaced the fan and temp sensor about 4 months ago, it has been fine. Not sure what it is . A relay maybe ?

[@a4l1f3]

My fan does come on but only when the car is already overheating. Could this be the switch? Thanks

[@ArtbyZen]

Hi, I have the same fan not coming on on Honda Civic 2003. But I also loose coolant with no leaks. Do you know why? Thank you

[@erikgarcia9250]

In case that the terminals on the sensor opened up how do we fix that problem?

[@davidborjas9577]

Already change the relay, I know the fan works, also the ECT located in the bottom of the radiator, I unplugged the ECT and used a paper clip to tested and both of my fans work, but still not working when I turn on the engine, can overheat my engine if I don't turn off, any idea?

[@searcherfor9]

Thanks for the video, it was a great help!

[@robertgarrett4425]

Thanks for the heads up that a paper clip pushed into the connector will cause the sensor to loose contact. I replaced the switch fans worked fine while parked but after a 30 min test drive fans stopped working. I checked the fan switch connector and it wasn’t making proper contact with the fan switch due to being spread out by the paper clip smh. Thank you!

[@BigDog50001]

Glad the video was able to help you out, thanks for the comment!

[@queenminks28xd64]

So were you being sarcastic? Or were you actually thanking him? Does the paper clip mess it up?

[@edithcisneros5330]

do you do this while the car is on?

[@policeh956]

Hi. Great video, nice clean and clear instructions. Thanks

[@ericg1149]

Do both power and ground go back to the relay?

[@joeyritzcaban3874]

What could cause the cooling fan to be constantly running after it automatically turns on? End effect is that the coolant temp drops too low and the engine starts to run below normal operating temperature. Thermostat, thermoswitch, ECT, relay, fan motor replaced with brand new parts.

[@sigimedellin5791]

Like teacher So clear and detailed explanation Thanks bro and congratulations

[@theblackproject-ard1221]

I'm currently having issue with my fan not turning on. I tried to put 12v power to the fan directly and it did turn on. However, it won't when turning on the A/C. I was thinking about the relay. I swapped both but still the same but I can hear a clicking noise when turning on A/C but still fan won't turn on.

[@scottcummins2710]

When you do the paper clip test should both fans turn on? I have a 2005 civic value package edition and only the condenser fan comes on when I tried that.

[@BigDog50001]

For THAT generation Civic (2001-2005), jumping the Radiator Fan Switch will provide ground to BOTH the Radiator Fan Relay AND the A/C Condenser Fan Relay, which should turn on both fans (if both relays and all wiring/fuses are good). The engine computer also has the ability to provide ground to the relays and turn on both fans. Bad Fuse #4 in the Under Hood fuse box, bad Radiator Fan Relay, bad Radiator Fan, bad ground (G201 behind right front bumper), bad wiring or connections are all possibilities for your scenario.

[@repssrepps]

Great video very informative thanks for your help!

[@osmaroh4988]

That tool box at the end 😍😍😍😍

[@BigDog50001]

lol

[@tstrotstro5038]

What if I have checked all of these and they’re are all good but still don’t work unless I Hotwire to prong 3 on condenser fan? 20 amp fuse under hood only has power to one side aswell

[@sarahnicole7829]

Does this video do me any good if I have a 2002 Honda civic? Or waisting my time ?

[@BigDog50001]

Of course I don't think you are wasting your time lol, but 7th generation Civics have a slightly different setup due to the radiator/condenser setup. 7th gen Civics have a fan switch (like the car in this video) but both fans will come on together on 7th gen Civics and the engine computer has control over both fans.

[@tmst2199]

So the interior blower motor relay is marked "HEATER MOTOR RELAY" on the fuse box cover.

[@CarolineRobinsonNHUK]

I have a 2002 Honda Civic Ex. My radiator fan is not working. I switched all the relays around that didn't make a difference so I don't think it is a broken relay. The wire bundle that goes to the radiator fan and plugs in just a few inches from the motor measures 12 when the key is switched on, but unfortunately the thing I think is the ECT switch for the radiator fan seems to be impossible to get to. It's to the left of the engine and just too deep for me to reach. I took a couple of brackets off the engine block that were interfering with my reach and still can't quite reach it. I tried reaching and pinching with pliers, all the time worried that if I get it off will I ever be able to get it back on again! Also not 100% convinced that this is the correct switch, but it looks just like another one that is easy to get to, but of course the easy one seems to be the ECT switch for the Air Conditioner fan. I tried your paper clip trick on that and the AC fan did come on - but that's not the one I am having trouble with. Is there a way to find a diagram somewhere to be sure the ECT switch I am trying to get to is actually the one I want? If it is, how on earth do I get to it? Do I have to remove the big black plastic thing to the left? I can't find any labeled pictures to identify what I am looking at. So frustrated. Your video looks wonderful it just doesn't match my car. I found this picture - www.samarins.com/reviews/img/civic_05_engine_large.jpg to the left of the vtec engine there is a great big plastic thing - I think it must have something to do with air or exhaust, between the 2 you can see a little light blueish circle. On my car behind (closer to the windscreen) the blueish circle and deeper is what I think is the ECT switch I am trying to test. Do you have any suggestions please?

[@socknetea]

Would the paper clip method on the switch located on the head also kick the fans on with keys turned to the second position the same way the switch by the t stat does?

[@BigDog50001]

There is only one Cooling Fan Switch for this vehicle, the one I showed in the video. I don’t advise jumping/grounding/applying power to any wires to the ECT or the gauge temp sending unit unless you know the circuit design (and know how to properly do bypass tests on them). They are not like the fan switch and doing it wrong can damage electronics inside the instrument cluster or the engine computer. See my pinned comment if you want to know the exact names of the switch and sensors.

[@tsubakitengai]

Nice, very helpful.

[@BigDog50001]

Glad it was helpful, thanks for watching!

[@JuanMunoz-hk4yt]

Awesome video man super helpful

[@BigDog50001]

I appreciate the comment, thanks!

[@mechanix6191]

This video is great! Excellent explanations.

[@BigDog50001]

I appreciate the comment, thanks!

[@Ihelpyouwithtutorial]

What would you say is excessive resistance at the fan switch? Replaced everything sensor wise with OEM Honda parts and still not coming on. I’m thinking I have a wiring issue and the circuit does indeed work with paper clip method. I see on pro demand there’s a junction back after the PCM. Is that the relay box?

[@BigDog50001]

There should be no resistance in switch, it is just a simple open/close switch that provides ground for the fan relay. If the fan works consistently with a paperclip then the issue is most likely located at/near the switch (the rest of the system is confirmed good with that test). Bad fan switch, bad connector(s)/connections at fan switch, air in cooling system near switch, vehicle coolant not getting hot enough to close switch, etc are all possible causes.

[@bakihanma7247]

I changed my temp switch and jumped the fan and everything works. Both fans turn on fine when I turn my AC on but when AC is off and temps get to 200 degrees it still doesn't turn on by itself

[@vinny1995]

on my 1995 honda civic, the culprit was the thermo unit sensor PN 37750-PH2-014. It's the smaller of the two sensors under the distributor. Either I didn't plug the wire in all the way until it clicks, or it was a bad unit that I replaced. After my engine swap, the cooling/radiator fan wouldn't kick in as the temp went past the half-way mark on the gauge, so I knew something was wrong. After testing the radiator fan by jumping it, testing the thermostat relay switch by shorting it, and replacing all related parts (thermostat, thermostat sensor (the one mentioned in this video), cooling fan relay in the fuse box under the hood, and the 7.5 amp fuse under the dash), what finally made it work was fixing the issue with the thermo unit sensor. Either it was a bad replacement part (I had taken out the original and replaced it with a Beck Arnley one) or I didn't plug the connector in all the way, I ended up replacing it with the original old one that I took out during the swap. It was either that or I didn't plug the cord in all the way. May sure it clicks and locks in tight. That could've been the issue. Anyway my fan kicks in now when the temp needle rises a quarter of the way up the gauge.

[@BigDog50001]

Thanks for the input!

[@vinny1995]

@@BigDog50001 I failed to say thanks for your video. Much appreciation.

[@DANNYN224]

Would the paperclip test work for a 2000 honda odyssey 3.5l v6

[@BigDog50001]

Not exactly. Those Odysseys are a bit more complicated due to high and low speeds for the fans. They have 3 relays for the fans and run the power in a series/parallel configuration through those relays to achieve low and high speeds. They also have two fan switches, A and B. Switch A closes at 200 degrees and Switch B closes at 210 degrees. The switches, Engine Computer and A/C all have inputs to control those fans. Unfortunately you have to know the circuit layout in order to test these.

[@TheDisgruntledMechanic]

Good video! I like the white board and testing. keep up the great videos.

[@BigDog50001]

The Disgruntled Mechanic Thank you Mike, I appreciate the comment!