Big A/C Problems
09-24-2002, 11:34 AM
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Big A/C Problems
Oy Vey... Yet another Audi Problem. This time, for some reason or another, the A/C Compressor doesn't kick in when the climate control system says it should. If I connect the two wires that engage the compressor clutch, the compressor kicks in.. This leads me to believe that there is something wrong with the climate control module.. I tried to replace the ISV control module (which, by the way controls the AC compressor switch).. but still no luck. HELP!?!? Has anybody had this happen to them before?
Jonathan
84 Audi 5000S (320,000KM)
Jonathan
84 Audi 5000S (320,000KM)
09-24-2002, 11:53 AM
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Re: Big A/C Problems
I have never had this happen, but it may just be a faulty climate control sensor (I am thinking the one in the dash). The compressor works, and the wires are good (you tested them together) and the ISV is new. As I recall, there is not too much else it could be. Maybe you could test it with a thermometer next to the dash sensor (An indoor/outdoor type, certainly not a rectal 
. The thermometer would give you the air temp at the sensor, and you could set the dash to something hotter than the temp outside- like you could set it to 78 when the temp outside is 60, and let the car run for 10 minutes to warm up. At that point, read the thermometer and determine where the air is coming from. When the car is warm enough, a valve opens and warm air comes through the vents in the dash (rather than the defroster vents). If there is enough of a temp difference between the outside air and the inside air and the heat is not working, that would show definitely a bad temp. sensor, though I would still check the wires to it. Anyway, I could go on forever (it probably seems as though I already have), but that is simply a possibility.
. The thermometer would give you the air temp at the sensor, and you could set the dash to something hotter than the temp outside- like you could set it to 78 when the temp outside is 60, and let the car run for 10 minutes to warm up. At that point, read the thermometer and determine where the air is coming from. When the car is warm enough, a valve opens and warm air comes through the vents in the dash (rather than the defroster vents). If there is enough of a temp difference between the outside air and the inside air and the heat is not working, that would show definitely a bad temp. sensor, though I would still check the wires to it. Anyway, I could go on forever (it probably seems as though I already have), but that is simply a possibility.
09-24-2002, 01:30 PM
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Re: Big A/C Problems
I would do a pressure check as DaveN says. The compressor will not kick in unless your pressure is right. May need to seal it and recharge it. Maybe a good time for the AC 134 retro fit conversion while you are at it. Check all the hi-pressure side connections real good including underneath by the compressor above in and around the condenser before attempting a charge. Add a can of oil/sealer also before any charge.
09-24-2002, 02:47 PM
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Re: Are you sure the ISV module controls the compressor
I think AC on is an input to tell the engine to Idle faster to compensate for the compressor load.
Like Dave and Bob said it sounds like the charge is low. On the '86 the low pressure switch is under the plastic cowl passenger side (not sure about the 84). Short the switch and see if the clutch engages. If it does you're low on charge. The low pressure switch will be on the larger diameter pipe.
Like Dave and Bob said it sounds like the charge is low. On the '86 the low pressure switch is under the plastic cowl passenger side (not sure about the 84). Short the switch and see if the clutch engages. If it does you're low on charge. The low pressure switch will be on the larger diameter pipe.
09-24-2002, 03:35 PM
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Re: Big A/C Problems
Thanks for all the advice guys... The AC system was charged in August with REDTEK and just a few months prior to that, was converted to 134. There are no leaks in the system and the system pressure appears to be good. I'm wondering, I live in Alberta Canada, not a warm place. Perhaps, could the audi be disabling the AC because the outside temp is below freezing?? Anyways, just a thought. As for the temp sensor on the dash: How the heck do I get it out?!?!?! Attempting to get it off, I broke off part of the little grill thing! Oy vey... is there any way that you guys know of to get it off without destroying it or my dash?!
HELP!
Jonathan
84 Audi 5000S (320,000+ KM)
HELP!
Jonathan
84 Audi 5000S (320,000+ KM)
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09-24-2002, 07:38 PM
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Re: Big A/C Problems
Are you positive that the clutch is not engaging or is it just that the air is not cold? If the clutch is definitely not engaging, then there is a clutch, electrical, sensor problem. If the clutch is engaging for sure and the air is still not cold, then it is in the AC programmer or control unit under the right side dash.