The air conditioning stopped working on my 2003 Civic LX. After some work with my mechanic, we found some o-rings that were causing freon to leak out. After filling the system, it was nicely cold and then became warm again. This time, nothing has leaked out and now the compressor won't turn on.

Following some Alldata directions, we traced wires and performed tests. These are the same results from this thread: https://honda-tech.com/forums/honda-civic-2001-2005-78/c-compressor-clutch-not-engaging-2962203/

The end result? The directions say to flash the PCM with the latest software. If that doesn't work, the PCM needs to be replaced.

One side note is that the thermal diode looks dead above the compressor, but jumping around it makes no difference and my mechanic tells me he's never seen a need to replace it to fix AC.

So, the compressor works but it won't start normally. What do you recommend? Try a software update or just replace the PCM? If I need to replace the PCM, what's a good source?

thanks,
Bryan

 

I'd try replacing the field coil and/or thermal protector. They're much-less expensive than a new ECU. (which you probably won't need)

 

Any good online sources for field coil and thermal protector? So far, the local Honda is the only place that can get them, they're not returnable, and they're $145 and $96.

 

http://www.hondaautomotiveparts.com/...R+%28SANDEN%29

Thermal Protector: $41.84 + S&H
Field Coil: $62.08 + S&H



Or you could try finding a used compressor, locally.

 

Thanks much. Reading about the thermal protector being a common issue, I'll try to test and wire around it first to see if that helps.

 

Yea, testing things instead of throwing parts at it is a good idea. You can bypass the thermal protector by jumping the 2 outside wires on it's connector. If the a/c runs that you've found the problem.

 

I assumed that by using AllData and/or the steps in this thread - that he had already tested the thermal protector.


Does the pressure check out? If so, did you check the pressure switch?

 

It's temporarily fixed now. The test done on the thermal protector apparently didn't work the first time. Tonight, I removed it, cut the two red wires going to it, joined them together, and the compressor is working now. We have cold AC again.

There's so little space there it's difficult to do much. When I add the new thermal protector, I may cut off the sensor part and connect it to the existing wires, as that looks easier than accessing the connector.

Thanks much to everyone here for their help with this. The technical info and well written posts here are what made me suspect it wasn't really a computer issue.