Air Ride Compressor Replacement
 

While this was done on an expedition the same basic procedure applies to many models and years. The crown Vic, Grand Marquis, Town Car location of this compressor is under the air box on the left front of the engine compartment. Follow my procedure and you wont have any problems as I have learned the ins and out of this system over the years. Hope this helps out as this repair is costly enough. If you need help diagnosing a pump that wont run see my diagnosis video too on you tube.