Welcome back:
First, technical information on this vehicle isn't available to me, but I will try my best to help.
The first thing I would suggest checking are fuses. Locate the power distribution box under the hood. Remove the cover. On the underside of the cover should be a legend of what each fuse is for. Locate the one for the air ride suspension and inspect it.
Here are a few links you may find helpful.
https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester
https://www.2carpros.com/articles/how-a-car-fuse-works
https://www.2carpros.com/articles/how-to-check-a-car-fuse
Lets start with that. Also, I need to know if the vehicle is sitting low in the rear.
Let me know what you find. Also, if you have the original owner's manual for the vehicle, it should help you locate the fuse box.
Joe
Wednesday, February 13th, 2019 AT 7:27 PM