Once again I find my 05 hse with a fault. I have replaced the compressor about 6 months ago with great results. Everything had been working fine. I know I have a bit of a air leak in the right front corner as it will drop some over night. Normally I start in the morning and it levels out no problem. The other day I kind of thought it hadn't picked up but with no fault I did not really think about it. Parked the truck for a few hour and when I started I had a fault. My first thought was the compressor not working. Sure enough I got out reached through the open window and started and no compressor running fault came back right away. Last night I put power directly to the compressor and it runs fine and builds air. So knowing that the compressor is operational, it would seem I have a switch somewhere that is not working. Where or what would be some places to start with? Does the ride height controls or pressure switch tell the compressor to kick in? I will say the days before the fault came on the cab of the truck was very hot from sitting in the sun.