I'm having a similar issue on my 2007 Expedition EL, with the rear air suspension not working. The rear end is completely lowered and will not come back up. I've verified that the air suspension compressor does turn on, but the suspension bags are not inflating (I assume so, because the rear remains completely lowered). I disconnected the airline/port directly at the compressor/dryer to try and determine if air is indeed coming out of the compressor. With that line removed from the port, should I expect to feel a strong air push out of the compressor, like what you get from a portable air compressor hose? Because it's more like a "trickle" of air.