Thanks for the info. Mine (05 4.4L) has the 'inactive' light on. Compressor pumps on its own at what seems like a normal cycle (meaning doesn't go on every 5 minutes), no sagging at any of the wheels, no sound of losing air from the wheel wells after pump cycle, BUT>>> the so-called passenger-side front Zenon light sensor arm was broken when I got the truck. I have replaced it last week. Wondering if the ECU uses info from that sensor to self-level or auto-detect issues? Can someone help please.
Thanks in advance.