The non-essentials...AC and A8 wheels.

Djdawson2 at Djdawson2 at
Wed Aug 7 11:38:37 EDT 2002

[ Picked text/plain from multipart/alternative ]
First thing you need to do is check and see if your compressor is engaging
when you turn the AC on.  If you open your window and switch it on, you
should hear an audible click from the compressor clutch.  Then visually check
it to see if it's turning.  There are a bunch of things that could keep it
from running/engaging, a few of which are:
-Low refrigerant level/pressure
-Bad multi function switch
-Bad AC relay,
-Bad evaporater temp sensor
-Bad high or low pressure switch

IMO, the easiest way to start (if the compressor is not engaging) is to jump
the compressor briefly.  There is only one wire running to the compressor.
Disconnect it and run a jumper wire from the jumpstart post (hot) to that
compressor wire (car not running).  You should both see and hear the
compressor clutch engage.  At that point, I usually start the car (clutch
jumped and engaged, high and low gauges hooked up) and see if there is any
cooling available, and what the pressures are.  You can still do this without
the gauges, you'll just have to check for cool air.  If you have gauges,
observe the pressures... you're looking for mid 30's on the low side, and
250-325ish on the high side at idle.  If you're not getting those pressures
(or cool air), your system is probably functioning correctly, but is simply

I just went through this in June with mine, but it was sort of unique.
Jumped, it was performing and had excellent gauge readings.  After locating
the AC relay (help from Bernie, the Bentley was wrong), I discovered it was
the evap AC probe that was shot.  I replaced that, and things seemed fine.
However, after driving for 15-20 minutes, the compressor would cut out again,
not to return until the car had been shut off and allowed to cool.  This
ended up being the multifunction switch.  I now have great cooling, but one
remaining problem that I haven't spent time on...  as I'm driving with the
fan on high speed (or auto), the airflow will switch to the floor.  It is
related to vacuum somehow, because if I let off the gas, it returns to the
normal vents... step on it again, and back to the floor.  On low fan speed,
it stays at the vents.  If anyone has any BTDT with this, I'd welcome
shortcuts... otherwise, it's back to the Bentleys.
Good luck, Adam,

More information about the 200q20v mailing list