A/C put out only hot air, light on HVAC panel blinked but no code when I checked at home. The compressor wouldn't cycle when I looked under the head bumping hood.

Compressor turned freely, voltage at compressor OK, jumped low pressure switch with positive results, compressor relay worked as required (but had evidence of having been removed before).

Disconnected battery to clear codes if set and ran the engine again. Now got 09 (low freon). Added Freon and it worked fine. The next morning it wasn't working. So, must be a leak. Got some leak check (visual light, not blacklight) in the system and the pressure sensor was slowly leaking out of the plastic connector.

I had some problems making sure I was getting the correct part since every parts place different nomenclature for AC parts. The sensor has 22536559 on it and there was no joy finding that. I found that is a discontinued PN with 22599559 being the replacement. AC Delco PN is 15-72104 and the correct nomenclature is air conditioning refrigerant pressure sensor.

Now I found the sensor available in lots of places for $80. Rock Auto was $42 + 5$ same day priority mail shipping. Can't beat that. GM Parts Direct is a few cents less but ground shipping is $13.

I thought I’d broken the sensor while troubling an ignition problem (recurring and not yet resolved). Once I removed it and cleaned it I could seen clear RTV around the crimp between the plastic electrical connector and the metal body. That explains the previously removed relay. Looking at the sensor and what one would cost at a FLAPS, I guess I could understand the attempt to repair it.

Bob Thomas 40th coupe