Carl Muckenhirn

Given the strange weather hear in Maryland, I've needed both heat and A/C (defrost).

But I don't get any A/C. Last fall, when replacing my sparkplug wires I accidentally disconnected the single wire going to the A/C clutch (pulled the wire out of the space). Replaced it and all was OK for a while. Now the compressor doesn't engage when I call for A/C.

I've checked the suspect wire and don't see any voltage (I'm expecting 12 v when the A/C button is pressed) between it and ground (the case of the compressor).

Does this indicate a problem with the controller? or should I still look into the wiring.

I can fully believe that the A/C clutch has given out. (the car's just now got 100K mi.) but would like to understand the problem before "fixing" things.

tia.

carl.

'89 C4

mojorizing

Hi Carl,
The A/C clutch has a fuse and relay in the engine compartment left side.
The fuse is 7.5 amps I think.

Later, Kevin

Carl Muckenhirn

Kevin,

Thanks, should have mentioned checked fuse, replaced relay (though it appears to have been fine, now I've got an extra!).

problem remains.

carl.

Adrian

Dear Carl,
The button on the controller supplies an earth to the relay. If you have lost 12V to the AC clutch you have either lost 12V to the supply side of the fuse or the earth to the relay coil or even the 12V to th eother side of the relay coil. This is easy to check. You can remove the relay and jumper the power and see if the clutch engages. If it does then you know the break is in the earth supply to the relay if it doesn't then the problem is in the wire or the clutch itself. Most of the time I see the problem in the wire, connector or the clutch itself.
Ciao,
Adrian
964C4

Carl Muckenhirn

Adrian,

Thanks, now I have reason to spend sometime in the engine compartment of my C4 ... in the cold garage.

carl.

540964

Carl:

If the system has lost refrigerant pressure, the low pressure cutout switch (located on the low side -suction- line in the trunk) will be open and prevent the compressor clutch from energizing. Easily checked with a voltmeter. The refrigerant hoses are known to leak. If yours need to be replaced, look at www.griffiths.com. They offer A/C hoses that have been rebuilt using a barrier hose that cures the leaks.

clashmin

Carl,

I am another marylander with a C4 with no air. I haven't even picked up the car yet (the transporter just made it to baltimore from california) but i know that the air doesn't work. i am anxious to see the results of your analysis. I just purchased a 1989 Black C4 with 108k. which part of maryland are you in?
-dave