2000 Venture(air compressor)

I have a 2000 Chevy Venture LT with rear air compressor for the self leveling suspension. Compressor is not working. traced problem to the relay next to the compressor and changed it , still not working. But when i bypass the relay and jump the power wires the compressor works. Does anybody have any suggestion. Is the another relay or fuse somewhere else, or a control switch for power. Thanks