Trouble Shooting

WARNING: This page is about a different car, the 2002 Ford Pickup. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: For trouble shooting not covered in this article, see TROUBLE SHOOTING in HEATER SYSTEMS article.

NOTE: A leak in vacuum control circuit may occur during acceleration (slow leak), may exist at all times (large leak) and may exist only when specific functions are selected (indicating a leak in that portion of circuit). Vacuum hoses used in passenger compartment control circuit are constructed from PVC plastic material. Vacuum hoses used in engine compartment are constructed of Hytrel®. Because of materials used, never pinch vacuum hoses off during diagnosis to locate a leak. A wood golf tee can be used as a plug when it is necessary to plug one end of vacuum hose for leak test purposes.

Verify customer complaints by operating system in all available modes. Carefully check following for possible cause of problems and repair as necessary:
- Loose, missing or damaged compressor drive belt.
- Loose or disconnected compressor clutch.
- Loose, misrouted or damaged vacuum lines.
- Broken or leaking vacuum control motor.
- Discharged A/C system.
- Broken or leaking refrigerant lines.
- Fuse(s).
- Blower motor inoperative.
- Compressor inoperative.
- Circuitry open/shorted.
- Disconnected, loose fitting, or incorrectly installed electrical connectors and pins.
If symptom(s) remain after preliminary inspection, connect New Generation Star Tester (007-00500), or scan tool, to Data Link Connector (DLC). Perform DATA LINK DIAGNOSTIC test.
If scan tool displays CKT 914, CKT 915 or CKT 70 = ALL ECUS NO RESP/NOT EQUIP, go to appropriate MODULE COMMUNICATIONS NETWORK article in ACCESSORIES & EQUIPMENT. Test and repair these circuits before proceeding.
If Powertrain Control Module (PCM) is not listed for a communication concern, turn A/C controls off and execute self-test diagnostics for PCM. See SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article in ENGINE PERFORMANCE.
If any PCM Diagnostic Trouble Code (DTC) are retrieved, perform appropriate test. See SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article in ENGINE PERFORMANCE. If symptom remains after repairs have been made, go to SYMPTOM TESTS .