1996 impala lm7 5.3
Hello everyone, I’m trying to connect my ac. I have a 411 pcm from psi with standalone harness. I kept all factory ac system and wiring. My problem is that it’s not getting ground to relay. I tried bypassing the high pressure sensor, replacing high pressure sensor. No luck. I check all wiring. With a scan tool I can command ac to cycle only when key on engine off. If I try with engine on it’s says ac pressure incorrect. Seem like my pcm is not reading pressure from high pressure sensor. I was looking for a binary or trinary switch but cant find any that fit. If anyone can help it will be great.