Alright got some a/c problems in my 95 formula I just got. Like it doesn't work Here's what I know. Compressor didn't kick on so I strapped a gauge on it. Since the compressor is off I got a reading of about 125 on both (they are equal with the compressor off). So it's 134 in it. The fan also didn't kick on with ac on. So I swapped some relays and checked fuses and nothing yet. Next I was going to jump the low pressure switch but I for some reason can't locate one. I see the high on top. So do these systems run with just the one switch? It's also a 3 wire job and I don't know how to jump it (or if it's even possible), so if you can jump it what wires do I use? And the last thing I found is that if there are any DTC's that are related to HVAC the pcm won't let the ac work. It also said there won't be an SES light. So when I got to work tomorrow I'm going to scan it but I would like to try some more things tonight before then (cause I hate when I can't fix something lol). TIA

 

When the compressor in my '97 GMC wouldn't turn on, I added a can of 134 to fix it. The A/C has a pressure switch that prevents the compressor from kicking in when the refrigerant is too low. Hope this helps

 

Well it had enough 134 in it. It wound up having a code for compressor fault. I cleared it and had a/c ever since. Pressure for the low side is right at 40, and high side I think was at 230ish so I'm golden there. Thanks though.