If your vehicle has air springs for the rear suspension, there should be a sophisticated set-up. If your system is similar to the Lincoln Town Car (or other Panthers) there is a control module that governs the compressor based upon input from sensors. One is the door ajar sensor, so that the compressor will not run if it thinks the door is open (and therefore someone may be entering or leaving the vehicle). There would be a height sensor that dictates when the compressor is required to raise or lower the car; is your ride height too low?
There should be a switch to power the system off, and a relay and fuses to allow the compressor to operate. Check the fuses and relay's. The compressor itself should have a drier to dry the air in the system and prevent ice blocking pressure relief solenoids. If the drier silicate is full of water it will block air flow and the compressor will not operate. The drier can be removed and the silicate put in an oven for 30 minutes to dry it out and then replaced. The compressor itself has a bushing on the shaft that is prone to degrade and overload the motor. I have heard of one person who replaced the bushing with a roller bearing to fix such a problem, otherwise the compressor may have to be replaced.
Hope this helps.
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Art
2000 Taurus SEL Wagon 3.0 Vulcan (daily driver)
1993 Taurus GL Wagon 3.8 Essex
1991 Mercury Grand Marquis LS 5.0
1986 Chevrolet 3/4 ton pickup 4x4 350 with turbo400 and 208 transfer case
1978 Chevrolet 3/4 ton pickup 4x4 custom 6.2 na diesel with turbo400 and 203 transfer case
Planning 2008 Taurus X in a year
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