Hi all,

My 02 CR-V LX A/C compressor failed last year so I had a local shop install a new one, but the mechanic had to ground the cooling fan relay at the fuse box for it to engage because he said the fan was missing a ground wire and he wasn't familiar enough with the car's wiring harness to properly fix the issue and recommended I bring it to a Honda dealership. I did that and they said they'd have to charge me $500 just to diagnose it, but I had already spent $750 at the other shop so here I am hoping someone has any idea how to fix this.

The heat and A/C work fine most of the time, but the cooling fan is always on because of the temporary fix and when it's hot out the A/C will stop blowing cold after 30-60 min of driving.

Does this issue make any sense to anyone? How could the fan wiring be completely missing ground? I haven't gone under the car to actually look at it, but if anyone has any advice it would be greatly appreciated. The car has 167K miles on it and runs fine otherwise, but if I can't get this fixed for a reasonable amount of money before the summer I may start looking for another car. I have 2 dogs, one of which is a pug that already has trouble breathing as-is lol so the A/C absolutely needs to work this summer. Especially since we're driving from Philly to North Carolina for vacation in August.

Thanks!

 

What controls the low speed on the fan is the sensor located in the radiator. the high speed or 2 fans running is when the AC is on.

The low speed has a relay on the fuse box to check.

 

My mechanic grounded the relay in the fuse box which keeps the cooling fan on. Not sure I'm explaining that correctly as I'm an electrical noob. What are you suggesting I look for or do exactly?

 

Post updated with photo of fuse box wiring - the ac compressor clutch relay is wired to the ac condenser fan relay then grounded to the frame. This is what keeps the AC fan on. Would love to know how to resolve the AC condenser fan ground issue so this hack isn't needed.

 

here is a YouTube video from bigdog50001. He is working on a 2003 Honda Element, but the system would be the same in a 2002 Honda CRV. Please note, his problem is NOT the same problem as yours, however,. he explains the overall cooling fan circuit well.

 

Thanks!! That was super informative, although I wish he actually showed the ground connections of the fans and where they connect to.

 

Jut do a google search for grounding points.

The car has quite a few, my 2004 CRV have 4-5 points in the engine. 2 of them are by the head lights. All that info is on the computer some where!

 

 

Thanks! I've seen that diagram, and I see those main grounding points are in tact. The mechanic mentioned it was specifically the ground for the AC condenser fan that was missing. That's what has me confused.

 

I think you are probably mistaken on what your mechanic said.

to clarify, if your mechanic thought the ac condenser fan lost ground then he would have hack-wired a ground to the fan. Instead, it looks like he hack-wired to your relays. That suggests to me that your relays lost ground. That is, of course, I’m assuming the extra wires are connected to the ground pins of your relays.

 

Yeah that makes more sense. How do I confirm that? Just trying to get to the bottom of the issue.

 

If you suspect the relay is bad, the relays are interchangeable between the 1 st fan and 2nd fan. You can have a broken wire inside the wire and visually look fine. You need to test it.

 

I did this before bringing it to the shop last year. To test if the AC compressor clutch relay (R5) and/or condenser fan relay (R8) were bad I swapped them with the working radiator fan relay (R6) and the radiator fan still came on. Is there another test I can try that would confirm whether there's a broken wire somewhere or not?

 

I have found it impossible to take people step by step on the internet and get a good result. The tools we have in our toolbox are different, and that often influences how we do things. You’re going to have to do a lot of self educating if you want to DIY this, YouTube is your friend (sometimes). Bigdog50001 comes to the rescue again:

 

I understand it's tedious trying to guide a random person on the internet. That's why I posted here after hours of searching, hoping someone may have dealt with this specific issue and knows more or less what the culprit(s) could be. I'll start with testing the relays, thanks for that video. I don't have a test light but I have a multimeter.

 

You have a system that has been modified. This is probably why the dealership quoted you $500 for the diagnosis. There will be no exact procedure in the Honda manuals to fix your system. In the big picture, the challenge is to 1) restore the car back to factory and then 2) diagnosing what’s was originally wrong.

 

There sounds like there may possibly at least two separate issues.

1. The cooling fans (radiator fan and A/C condenser fan) both suppose to run at the same time. Whether the AC is on or not, if the coolant temperature reaches ~ 199 degrees at the radiator fan switch (switch located at bottom of the radiator), both radiator and AC condenser fan should turn on. If you turn on the A/C; both fans also suppose to run.

The relays for the cooling fans are grounded by either the radiator fan switch or by the ECM/PCM.

2. The A/C compressor clutch relay is separately grounded by the ECM/PCM. There are various things that can cause the ECM/PCM to not send the ground to the A/C compressor clutch relay. 1) Heater control panel needs to send ground signal to ECM/PCM, 2) A/C pressure cannot be too high or low at the A/C pressure switch, 3) ECM/PCM has to send the ground to the clutch relay. An issue anywhere along the circuit (e.g. wiring, component, A/C pressure, etc.) can cause the A/C to not operate.

 

I agree with the above.

I think the difficulty here is that the OP needs to gain experience on what techniques and tools are needed to do automotive electrical testing.

 

To begin checking, the jerry rigged wiring (which is probably just directly grounding each relay) would need to be removed from the 3 relays.

Like I stated in the previous post, ground is from either the radiator fan switch or PCM/ECM for the radiator fan relay and condenser fan relay.

After, you remove the jerry rigged wiring.

To check the two cooling fans:
If the A/C works, turning on the A/C should make both fans run.

This other check is to see if ground can travel through the cooling fan circuits from the radiator fan switch to the relays.
1. Unplug the grey connector for the radiator fan switch. Insert a spare piece of wire or a small paper clip in grey harness connector (to jump the cavity terminals). Doing this will supply ground to the two fan relays.
2. Turn the ignition switch to the ON position (car does not have to be running).
3. Does both cooling fans run? (They both should run).
4. If only one fan or both fans don't run, then report the results.






A/C issues
Checking why the A/C doesn't run or only intermittently would probably require you to bring to a professional to check some of the various components in the circuit. I mentioned some of them in my previous post.

 

Thank you for the detailed instructions! Much appreciated. I'll follow them and report back this weekend.

 

For now to do the test, you may just want to disconnect the end of the jerry rigged wire at the ground, instead of removing the other ends of the wiring from each of the 3 relays. Therefore, if you can't diagnose and fix any issues, you could always quickly reconnect the jerry rig to get something operational.

 

I removed the rigged wire from ground, unplugged the connector from the radiator fan switch, put in a paper clip touching the metal contacts, turned the key into the on position, turned on MAX AC and only the radiator fan (driver side) came on.

 

Good luck @checazzo .you’re starting to get somewhere. I’m going to take a back seat to @tech8 That post #19 of his would have taken me 3 hours to type, edit the photos, and add pics from service info sources.

 

Thanks @ajchien! Very grateful for @tech8 time for sure.

 

Report the results for the following separate checks:

Check 1: Jump the radiator fan switch connector with the paper clip; but, do not turn on A/C. Turn ignition to ON.

Check 2: Do not jump the radiator fan switch connector, leave unconnected to switch. Turn on A/C (does not have to be MAX A/C).