I have a 2000 Cadillac Dts that has the rear air shocks completely inflated and the back sitting higher than the front. Does anyone know how to reset the suspension or any idea how to level out the rear again?
Not actually air suspension. These cars have coil springs at all 4 corners, oil filled struts up front, and oil filled shocks in back. The shocks have air bladders for ride height control only.
The problem is most likely a bad ELC pump exhaust solenoid. You'll have to pull your codes. There's a "sticky" thread on how to pull DTCs at the top of the FWD Deville/Fleetwood page. Make sure to include the code definitions.
If you're not getting a code for the exhaust solenoid, it's probably fine electronically, but it or the air lines may be full of gunk. There's an air dryer on the pump. Over timeout gets overwhelmed, and the pump and lines can get clogged.
For now, you can disconnect the air line from one shock to vent the system.
To check the rear Electronic Level Control for proper operation - get 2 assistants. Pop the trunk. Turn the key ON and listen for the leveling compressor to run for a second or two - about 8 seconds after Key: ON. This is a preload and proveout sequence. OK ?? All 3 of you hop onto the open trunk lip. The compressor should run again to level the car. OK ?? All hop off and you listen in the RR wheelwell for escaping air as the system again levels the car.
If it doesn't work this way you have a faulty compressor, control head, height sensor(s) or bad shock bladders. The air bladders have nothing to do with suspension control - only with rear height. The struts/shocks and springs are the suspension controls, and your DTS has a constantly active control system that reacts to changing speed and road conditions. It is not "air suspension", it is Constantly Variable Road Sensing Suspension - CVRSS F45.
Here's your rear suspension - see the coil spring ?
Ok I'll try that out but I disconnected an air line and bleeded the air out connected it back and turn the key to on and the bags filled back up. So the compressor works. Is there a way to test the height sensor see if it works?
In the rear passenger side wheel well, the height sensor is bolted to the body, and connected to the control arm with a small ball and socket link. Pop it off at the control arm. Moving it up should turn the compressor on, down should vent air. There will be a delay, so you'll have to hold it in each position before the system reacts.
If you position it too far up, it will set a code for the position sensor and the system won't inflate or vent.