I just had one come in and made an easy to follow diagnostic video to see why that air compressor is not coming on and why your back end is down to the ground. Air ride truly is simple to diagnose and fix if you understand the system. This procedure applies to Expedition and Navigator pre 2003. Hope this helps!

 

I am missing the command ground. I can supply the ground and compressor comes on and builds air pressure but does not inflate bags

 

What year