Any time a raise function is performed, there is a +12 volt signal to turn the HWH auxiliary air compressor on. Push any RAISE (UP ARROW) button to check the air compressor. Some compressors have a pressure switch which will not allow the compressor to run if the vehicle has adequate air pressure in the suspension. Check the air compressor with the engine off and the system air pressure below 90 p.s.i.
This manual shows a common compressor arrangement used. Other compressors may be used. Consult the owners manual or HWH Technical Service for specific diagrams.