My 06 Envoy Denali AC was working fine. I bought the truck used in 2014. I never touched the AC system. Today it’s 65 degrees and the compressor does not run. I put the AC gauges on it and I read 110psi on the high side and low side. I understand the high side and low side will equalize to the same pressure after the compressor stops. But as I think about the pressure, it makes no sense to me. How on earth can the pressure be 110psi on both sides on a cool day. According to the temperature/pressure charts, that’s way too high for a 65 degree day. R134a should be at about 65psi. If it was 95 degrees out, then sure 110psi make sense.
I initially checked a few things like the low pressure switch (appears to be closed and that is apparently fine) and the relay and fuse. It looks to me like the PCM is not commanding the compressor to engage. I don’t know why yet but I’m wondering if the pressure was too high. I can jump the relay and try to make the compressor run - but those pressures concern me.
I initially checked a few things like the low pressure switch (appears to be closed and that is apparently fine) and the relay and fuse. It looks to me like the PCM is not commanding the compressor to engage. I don’t know why yet but I’m wondering if the pressure was too high. I can jump the relay and try to make the compressor run - but those pressures concern me.