So today I notice while my 2002 envoy was parked in the garage that the air compresser was engauging even when the truck is off. This worries me because I dont want it to burn itself out. Im not sure exactly why this is happening, especially when the truck is off. If any one has any suggestions that would be great. I disconected the battery already. Its a fairly new compresser, I changed it 2 years ago. and it is expensive to change. HELP!