RSKtakR

2002 Civic HX coupe with 5spd and 189k miles, bone stock and never had any problems, I am the second owner and owned it since 125k miles. The car was sitting for a little while and the brand new battery died so I replaced it. After that, the AC doesn't blow cold. The AC button lights up when pressed, I jumped the AC evaporator temp sensor in the drivers lower foot well and no change. I checked/swapped around the AC relays under the hood in the passenger side fuse panel, no change. I checked the AC fuses and they look good, I took the car to a local mechanic and he was able to jump some wires and get the compressor to come on and blow cold air. I let the car run and get to temp until BOTH fans came on by themselves so I know both are working correctly.I replaced the original PCM ending in L04 the first time (had the immobilizer settings transferred over) with a re manufactured PCM ending in L05 and still no change. I took the car to a local Honda dealer and they were able to jump things and get the system to blow cold too. Then they were about to take the compressor out to replace it and the AC system worked all by itself then stopped working so they didn't pull anything apart. They said they found a short in between the re manufactured L05 PCM and the original multiplex and wanted to replace the PCM again, I told them no and brought the car home. I replaced the multiplex with a new OEM Honda part, still no AC change. Then I bought another brand NEW OEM Honda PCM ending in 417 from Honda (immobilizer settings transferred over), I just installed it and still no change. I am completely baffled here and so is the Honda dealer. They had the car for 4 days or so and said there is a short after the 1st replacement L05 PCM but before the original multiplex. So to sum it up, I've put two new PCM's (went from the original L04 PCM to a L05 and a 417) in the car and a new multiplex and still no AC coming on. Any suggestions?

BrotatoChip

Was the pressure in the system every checked? I sure hope so if it went to two different mechanics.

RSKtakR

I know the first mechanic didn't check the pressure, but I think the Honda dealer might have checked it before they determined they were going to pull the compressor off to replace it but I'm not sure. I am doing some easy trouble shooting with a meter just checking voltages here and there while I have the car and time. The car is scheduled to go back to the Honda dealer tomorrow afternoon for them to try and diagnose it again since I have replaced the PCM and the multiplex and the same issue is still present at no charge. I did an AC self check yesterday and the system didn't shoot me any codes, I also jumped the AC pressure switch with the key on accessory and the ac on/off and have no voltage there. I am checking the AC control panel inputs today and after that, I think that's about all I can do here probably. The system was working great prior to the battery failing and when the compressor comes on and blows cold air when things are jumped however I think it is FORCED to come on when jumping things around weather there is refrigerant or not. When the dealer was about to pull the compressor off to swap it out, they said the AC just started to work (compressor, fan and blow cold air) at one point as the system is supposed to so they decided to not pull the compressor. I think they told me that they had to evacuate the system and then put new refrigerant in it with a dye to check for leaks before they determined the compressor needed replaced.