2008 Envoy Denali with 120k mi in excellent well maintained condition. Problem started a few years ago, first time it was hot out and of course the AC quit blowing cold and the check gauges light came on. Pulled over and checked under the hood all was OK. Did the basic checks and found nothing. Engine code for engine not warming up fast enough. Monitored system with scan tool and all looked fine and temp gauge worked. Did the Google and the general opinion then was thermostat so I put a thermostat in and serviced the cooling system. Everything was fine for a while and here we go again. Did the whole deal over again this time with a factory thermostat. Again monitored the system and all functioned just fine. Did the cluster control function and all was good as the new Google searches went from thermostat to stepper motor. Did some research and saw that the BCM would default the gauge to cold if it was told that the temperature didn't warm up fast enough which I guess it compares IAT to coolant temp. I now carry a 5/16 battery wrench so when it happens and I'm out and about I can disconnect the battery and get the system functioning again so I have AC. More Googleing and I'm still getting dead ends and wild guesses and no fix but plenty with the same complaint. My theory is the PCM needs an updated program to stop this BS but I don't have any contacts in the dealerships any longer.
Has anyone found a fix for this? I see on this forum it's still an ongoing complaint but I don't see a fix.
Has anyone found a fix for this? I see on this forum it's still an ongoing complaint but I don't see a fix.
