1. Power and Ground to the Compressor:
* Check the fuses: Locate the fuse(s) related to the air suspension system in your fuse box (under the hood and possibly inside the cabin). Verify they're not blown.
* Check the relay: The compressor likely uses a relay. Locate it and check if it's clicking when the system should be engaging (you might need a helper to cycle the system). A non-clicking relay needs replacement.
* Inspect wiring: Visually inspect the wiring harness leading to the compressor for any signs of damage, chafing, or corrosion. Pay close attention to the connections. A poor connection can interrupt power.
2. Height Sensors:
* Check for errors: A malfunctioning height sensor *could* prevent the compressor from running. You'll need an OBD-II scanner capable of reading your vehicle's specific codes (often requires a Ford-specific scanner). The codes will pinpoint whether a height sensor is the problem.
* Wiring to sensors: Check the wiring harness leading to the height sensors for any issues similar to those mentioned above (damage, corrosion, loose connections).
3. Air Suspension Control Module (if applicable):
* This module acts as the "brain" for the air suspension system, reading sensor inputs and sending commands to the compressor. A faulty module is less likely than the simpler problems mentioned above but is a possibility. Diagnostics are usually necessary to identify module failure.
4. Solenoid Valve:
* Involvement: While the solenoid valve (or valves) control the flow of air, a faulty valve will likely cause uneven ride height (one side down) rather than prevent the compressor from running *entirely*. It's more likely a *symptom* than the *cause* of the compressor not working in your case. However, testing its operation is still a good idea.
5. Low Air Pressure:
* Check system pressure: This is crucial. If the system has already reached its desired pressure, the compressor won't run. Check the air pressure within the air suspension bags (you might need a specialized gauge). If there's a leak, the compressor will keep cycling to compensate.
Troubleshooting Sequence:
Start with the simplest checks (fuses, relay, wiring) before moving on to the more complex components (sensors, module). Using an OBD-II scanner to retrieve any diagnostic trouble codes (DTCs) is highly recommended. These codes give a more accurate indication of the problem than guesswork.
Important Note: Working with air suspension systems requires understanding of vehicle electrical systems and safety precautions. If you're not comfortable working on your vehicle's electrical system, it's advisable to take it to a qualified mechanic specializing in air suspension repairs.
