Air suspension stay on HIGH position, the SELECT button is showing on NORMAL. I try to push UP or DOWN, the green led indicator doesn't respond, just stay at NORMAL position and NO flash at all. Any suggestion ?

 

Stuck on the high position, even after driving? More than likely a faulty compressor exhaust solenoid. It's responsible for venting air to lower the truck. It should have a chassis code stored if that's the case.

 

Yes, It is stuck on the high position when I drive on highway. I try to SELECT to High or Low position. But the SELECT indicator (green led) doesn't move. If the system runs good, this led should move up down and flashing first. then we can hear air compressor noise later . Am I right ?

 

Yes. When going from high to low, you should hear it hiss as its venting. Low to high should kick on the compressor.