n8dogg

Before anyone posts please read... I am trying to get some helpful answers, not the typical "make sure there is enough freon" etc...

My car is a 2003 LX Coupe, pretty base car, 101k miles. I just got it about a month ago. I knew the A/C did not work. OK no biggie, I'm a mechanic by trade so I can fix it... well I thought, but the Honda schematics are a bit confusing to me. Being said, here we go...

First I connected the A/C machine to the lo and hi ports, she was definitely low on charge. I recovered only 4oz of charge from the system. It does hold vacuum so any leak that it may have is minute as can be.

I then charged the system and what do you know, the A/c works. Push the A/C button on and the LED illuminates, compressor and fan kicks on. A/C blows cold, everything seems good.

The next time I got in the car, the A/C doesn't work again. LED comes on the A/C switch, but no compressor and no fan. I figured there must be a bigger leak than I thought, so I look and don't see any leaking seals or components. I put the gauges on the ports and it shows good pressures.

Just for sh*ts I recovered the charge to find out for sure how much is in the system. I pulled out 1lb and 2oz, indicating the system had enough freon. Well I charged her back up and still no A/C.

I went on All-Data and followed there diagnostic steps for No A/C, Compressor, and Fan operation.
Checked for power at the pressure switch, no power.
Measure resistance between both HVAC control connectors and resistance is below spec.
All-Data says to swap a known good HVAC control unit and try, I do not have one.

So according to All-Data my HVAC control unit is bad. I have one coming from the salvage yard. Should be here today.

After tested the unit I performed the self diagnostic procedure by turning key off, turning blower speed dial to off, and pressed the recirculation button and defrost button together while turning the key to on. The HVAC did its checks and no DTCs flashed. I started the car and the A/C started working each and every time I pressed the A/C switch.

I'm hoping the replacement head unit will fix the problem. I figured I would post in case anyone else has experienced a similar issue and could help. Thanks for taking the time to read this.


*** EDIT***

*Update 4/20/11*

Well the salavage yard brought me the replacement HVAC control unit, as well as the whole radio bezel, hazard switch and A/C push buttons (that was nice of them :p). I removed the old and connected the replacement. Performed the self diagnosing/reset procedure on the HVAC unit. Turned the engine on and tried the A/C....
.... NO cigar! A/C light illuminates... no compressor engagement.

So that blows... ha not cold tho!

I jumped the compressor relay and the compressor does turn on, how ever... the engine just about stalled as if the compressor was seized! This is confusing because when I was able to get the A/C to run the compressor acted normal.

What gives? Any ideas?

It Wasn't Me

Have you checked to make sure there's enough freon? Ahaha! Sorry, I had to.


Sounds like you're well-on your way to figuring this out on your own. Interested to see what you come up with.

n8dogg

Ha ha, Thanks. So far, not so good. I edited my first post if you'd like to read.

n8dogg

Bump in efforts to get some help 8'(

It Wasn't Me

Interesting.

Honestly, as much as I'd like to help, it sounds like you have all the tools necessary to figure this out. It's just going to take more time and patience to narrow it down and find the culprit.

The fact that it's intermittent leads me to believe it's a connection issue. Loose wire terminal somewhere. (such a PITA to find)

Hopefully you can get it sorted out, and share what you find.

n8dogg

Thanks, I'm sure I will but I just had hopes that this might be common or someone who has came across similar concerns could help shave some time I got into this issue.

What I thought was intermittent may not really be. After I evacuated and charged the system it worked, but only that one drive cycle. Ever since it has been not working and constant. So it should help with diagnostics, hopefully.

Based on the fact that the fan and compressor do not turn on, and I can get the compressor to come on by jumping the relay, I am pointing towards either the pressure switch or thermal switch on the compressor.

Anyone know how big a pain the compressors are to remove on these? I think I may pull it off so I can inspect it properly.

It Wasn't Me

I assumed you replaced the pressure switch and/or thermal protector, that's my bad for not asking.

Pressure switch is definitely worth checking out.


Disconnect the pressure switch 2-pin connector. Turn the ignition on, and measure the voltage between terminal #2 (red wire) and a body ground.

Is there voltage?

n8dogg

I did not replace the pressure switch or thermal protector. When I was following the diagnostic chart I assumed there would be 12v at the pressure switch connector because they say I should find battery voltage. So I used a test lamp. The lamp did not illuminate, indicating there is not full battery voltage... there may be some voltage I can check with my DMM tomorrow.

n8dogg

Bump for some help... hopefully!

n8dogg

I am surprised that there has only been one member offering help. The Civic is probably the car with the greatest population of DIY'ers... someone's gotta have some idea!

sharkbaithal

Having similar intermittent problems with '88 CRX Si, 200k miles. When turning on a/c, it might blow cold in 5 seconds, or take 20 minutes. Once it is on, it might work for 10 minutes or an hour. Maintains charge with no apparent leaks.

Took it by a shop and the initial thought was thermostat or compressor coil (mech had seen same problems with other honda's). Both checked good. Next time I can get it in, will check for proper voltage (lack of?) for pressure switch, computer, and/or actual switch in dash. Of course while the mech was trying to troubleshoot the problem, the a/c wouldn't "cooperate" and worked.

ernieey

Hey man, mine was doing the same thing, please check out this youtube video which may help you out.

http://www.youtube.com/watch?v=s6ioJ...&feature=feedu

God bless and best of luck!