trulytex

1990 Corvette - Cannot get the HVAC COmpressor to turn on. The freon has been checked and I switched it over to R134. I can force the compressor to turn on by jumping power to it from the battery with a wire and it blows Cold. I checked the Relay behind the Instrument Panel and it checks out OK. The Green Light flashes above the AUTO button when I turn on the AC. Does this sound like a bad AC Controler? Is there a way to test it?

LTxDave

Did you check the pressure switch in the AC line?

Flame Red

+1 - I had the same problem and the pressure switch got clogged after conversion to R134. Autozone stocks a replacement. I believe there is also a small screw that one can adjust the switch for the different pressure of R134, but unless you know what you are doing I would leave it be. Mine has been fine now for quite a few years after I replaced it.

SunCr

Would help to know the static and operating pressures.

The flashing LED indicates that a problem has been detected and nothing is going to work until it's fixed. It may be a low gas code; particularly if you had to rebuild it. Start by disconnecting and reconnecting the battery which will clear memory and then see what happens.

trulytex

Well, stopped by the local dealership this afternoon to return their AC Vacuum that they loaned to me and talked to one of the techs and he told me the place to start is to disconnect the Battery to clear the codes. So that is exactly what I did and PRESTO, the compressor came on and ran for 20 minutes with no problem. I had to do the same thing with my 1987 Cadillac Allante', but thankfully they placed a decal right by the compressor stating that.

Such a small fix to cure such a Big Problem. Thanks for all of Y'all's help.