A/C Compressor Runs Constantly
Symptom: Regardless of whether the "AC" switch is pressed in or not, the A/C compress runs constantly.
>> The only time I don't have power to the compressor is when I have the selector
>> switch on the heater control to "off". At all other times the compressor turns.
>> I should mention that I have a manual system. When I press the "AC" switch,
>> the light comes on but as far as I can see it makes no difference whatsoever
>> since there is always power going to the compressor.
The only things that will cause the compressor to stay on are the relay (if it's stuck closed) or the dash panel AC switch if it's holding the relay closed. The AC switch has two contacts-- one pair goes to the relay, while the other illuminates the lamp within the switch itself. The switch on my car is part of a panel between the the controller and the radio. There's a reset switch for the electronic display (not a problem for pre-'89 cars), and the central lock button. The AC switch has its own little plug-in connector, and can be easily checked with a meter after it is loosed but not removed from the dash. If the switch is bad, replacement of the little panel assembly is the only practical solution. Give 928 Int'l or David Roberts a call to get the part you need.
The relay has two contacts also, which can be checked by removing the controller and the covers. The relay itself is that little [blue on my car] cube on the controller, about 13mm wide, 20mm long, maybe 10mm thick on the board. The contacts are screened on the cover, so it's just a matter of tracing a few connections with the ohmmemter to find if it's stuck. If it is stuck and you don't want to play electrical surgeon, I'm sure replacement controllers are available from Mark or David. I found the substitute relay at a store just minutes from 928 Int'l. I figured that if I buggered the old unit I have a fallback local to me; you may not have that option so handy, so getting a replacement controller may be the best option for you.
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