Only one relay in the system, for the compressor, difficult to say whether the contacts were welded, but if they were, compressor will always run. Or could be energized by the level module itself. That module does have a time delay built in, have to stand on my back bumper for at least 20 seconds before the compressor starts to bring it back to level. Jumping off the bumper, takes another 20 seconds before the vent opens to drop it back to normal again. Believe there is also a timer so the compressor can only run for a brief period of time. Otherwise with an air leak, it would run continuously.
Back in 99, when I purchased my 92 DeVille, neighbor dealer let me take it home of three days, was very concerned about the rear shocks, looked rusty. Air leaks are usually the major problem with these things. I did buy the car anyway, and to my amazement, when I got it home, he put two new air shocks in the trunk. 12 years later, they are still new in the box, has been troublefree. More than likely because I have two new air shocks to put in.
First go around with this system was in a 73 Fleetwood, used a vacuum pump type compressor, tank had rust holes in it,
that with solder and a thick coat of paint, then that steel tube had to be replaced all the way back, plus new shocks, and cleaning up that level control. That was a huge car. But nothing like that 89 Continental I was dumb enough to buy with four air struts that went flat. Dealer wanted 750 bucks for each shock! That couldn't be driven period, only about 2" of ground clearance, got rid of that thing.