1997 STS Air Ride Control
 

The air shocks are fully pressurized and will not release. Ride is quite harsh. I replaced the ride height control modules at each rear wheel, but no effect was noticed. Added weight of 500 lbs to the trunk made no difference. The car did not lower and the air pump did not turn on. Some of the relays behind the rear seat feel hot. Is there a trouble shooting procedure to follow to diagnose this problem? I have found these parts can be quite expensive to replace on a see-if-this-works basis.