* Low Air Pressure: This is the most common cause. Even if the compressor *is* functional, it won't run constantly. It cycles on and off to maintain pressure. If a leak exists in a strut, line, or bag, the pressure will drop below the threshold, triggering the light. The compressor may not start because it senses sufficient pressure (or close to it) and doesn't need to operate yet. Check the air suspension system for leaks visually (look for signs of rubbing or damage on the air bags/lines).
* Faulty Air Suspension Pressure Switch (Sensor): This sensor monitors the air pressure in the system. A faulty switch can provide an inaccurate reading, causing the light to illuminate even if pressure is adequate or the compressor is working. This would prevent the compressor from activating, as the system believes there's enough pressure.
* Air Suspension Height Sensor: These sensors detect the car's ride height. A malfunctioning sensor could send a false signal, indicating a problem even if the system is otherwise fine. This might prevent the compressor from engaging.
* Bad Compressor Relay: The compressor is controlled by a relay. A failed relay won't allow power to reach the compressor, even if the compressor itself is good.
* Blown Fuse: Check the fuse for the air suspension system in the fuse box. A blown fuse would prevent the compressor from functioning.
* Wiring Problems: Damaged, corroded, or loose wiring in the air suspension system can prevent the compressor from receiving the signal to operate or prevent the light from functioning correctly.
* Control Module (Air Suspension Control Unit): The control module manages the entire system. A faulty module can cause various problems, including the compressor not running and the warning light illuminating. This is often a more expensive fix.
* Compressor itself (Less Likely): While less likely given the light coming on *without* pumping, it's possible the compressor is faulty but still sending a signal indicating a problem to the control module. A mechanic can test the compressor directly to confirm functionality.
Troubleshooting Steps:
1. Check the air suspension system for leaks: This is the most crucial first step.
2. Check the fuse: Replace it if necessary.
3. Inspect the wiring: Look for any damage, corrosion, or loose connections.
4. Use a diagnostic scanner: A scanner capable of reading air suspension system codes can pinpoint the exact problem. This is highly recommended.
If you're not comfortable working on the system yourself, take your Town Car to a qualified mechanic. They have the diagnostic tools and expertise to properly diagnose the issue. Attempting repairs without proper knowledge could cause further damage.
