Also, the wires and their connections going to the relay have been known to go bad. The power wire on my red Mark was bad and I had to replace it. I've also heard of the trigger wire from the air ride module going bad.
Here's a wiring diagram for checking the wires to the relay:
I swapped out the abs relay with the suspenion relay.. and i'm off the ground and able to drive this beast.
Once the car was off the ground, i drove around the block and then parked it for the night. I turned off the air ride and the bags hold air over night.
I only heard the compressor kick in once when the car was off, while i washing the car. I will most likely install the new air bags/struts in the weeks to come.