2004 AC gone.

Oahuyahoo

Member
Joined
Jan 5, 2011
Messages
15
Noticed the AC started working intermittently, first started off slowly, then more often it would not work now it doesn't come on at all. Installed a new climate head unit and still no go. Going through the codes the dic states "no communication". Checked the fuses all good. HELP anybody!
 
what's the pressure on the low side port? That's the port you use to add freon, the parts store gauges are not very accurte but good enough to see if it needs a charge or not... a very slow leak could cause what you describe so check if you're low on freon.
 
Is there any noise from under the hood? I did the compressor in the c5 last spring, the c5 compressors are notorious for eating themselves. Royal PITA job, but generally speaking can be done fairly easily. Do you have a Harbor Freight tools near by? They have a basic automotive gauge set for around $40 and you can find the 20% off coupons just about everywhere. Real test will be to put gauges on it and see what's actually going on inside. Most likely a bad compressor will fill the orifice tube filter up with gunk and you'll max out pressure on the high side. If that happens, just plan on replacing the condenser when you do the compressor. Believe me, they're virtually impossible to flush for less than the cost of a new condenser.
 
Hey Gary how are you doing? This thing is driving me nuts, took it to the dealer and he couldn't even fix it. I'm lucky and I'm not. It's got to be an electrical problem, the entire system is dead. Now we all know about chasing electrical gremlins on a vette.
 
is the compressor kicking in at all ? If not it could be as easy and simple as the low pressure switch... there's a high pressure switch too... both switches can be faulty and prevent the compressor from running. Both switches can be "bridged" with a paper clip ....

Check with a voltmeter if you're getting 12V at the compressor. If there is 12V then it might be seized up.... or the clutch is not working...

the dealer should have done these simple tests.... or simply supply 12V to the compressor and see if it runs or not....
 
The entire system is dead, nothing turning on and no air of any kind blowing.
The control module in the car does nothing, doesn't even come on.
 
Are there any codes? I guess I've been kind of lucky (knock on wood), I haven't really had any electrical issues.
 
Shit Jeff. I'm at a loss. The "no communication" pretty much confirms that it's electrical somewhere. The fact that you put in a new head unit and still have the problem leads me to think it's somewhere in the harness. Haven't had house mice in the garage, have you?
 
ok, you already replaced the head unit... I hope they let you return it if it turns out to be somehing simple and the old unit was fine.....
Check if the compressor works by supplying 12V to the compressor switch/clutch. Obviousl the engine has to run when you do this - if the compressor works you can then measure high and low side pressures.... if these are fine then it's purely a electric problem and since you replaced the hed unit it must be the harniss or fuse.... now, is that head unit a known good one or new or from a junkyard ? any chance you bought a dead head unit ???
 
New unit came with the car.
ok, you already replaced the head unit... I hope they let you return it if it turns out to be somehing simple and the old unit was fine.....
Check if the compressor works by supplying 12V to the compressor switch/clutch. Obviousl the engine has to run when you do this - if the compressor works you can then measure high and low side pressures.... if these are fine then it's purely a electric problem and since you replaced the hed unit it must be the harniss or fuse.... now, is that head unit a known good one or new or from a junkyard ? any chance you bought a dead head unit ???
 
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