LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Ford >> 2002 >> Crown Victoria Base, 4.6 9 >> Repair and Diagnosis >> Heating, Ventilation & A/C (HVAC) >> HVAC Control Systems >> HVAC System - Manual >> Trouble Shooting >> Preliminary Inspection

Preliminary Inspection

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.
  1. Verify customer complaints by operating system in all available modes. Visually inspect for obvious signs of mechanical or electrical damage. 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.
    • Broken or leaking refrigerant lines.
    • Open fuse(s).
    • Blower motor inoperative.
    • Compressor inoperative.
    • Circuitry open/shorted.
    • Disconnected electrical connectors.
    If an obvious cause for an observed or reported concern is found, correct cause (if possible) before going to next step.
  2. If cause for an observed or reported concern is not found, connect a scan tool to Data Link Connector (DLC). If diagnostic scan tool communicates with vehicle, go to step  3. If diagnostic scan tool does not communicate with vehicle, ensure that program card is correctly installed, check ignition switch position or check scan tool connections to vehicle. If diagnostic tool still does not communicate with vehicle, see diagnostic tool operating manual.
  3. Perform DATA LINK DIAGNOSTIC test. If scan tool displays CKT 914 or CKT 915 = ALL ECUS NO RESP/NOT EQUIP, see appropriate MODULE COMMUNICATIONS NETWORK article in ACCESSORIES & EQUIPMENT. Test and repair these circuits before proceeding. If scan tool displays SYSTEM PASSED, retrieve and record continuous Diagnostic Trouble Codes (DTCs), then erase DTCs.
  4. If any Diagnostic Trouble Codes (DTCs) are retrieved, perform appropriate test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If symptom remains after repairs have been made or no DTCs related to concern are retrieved, go to SYMPTOM TESTS .
scientia non olet · About LEMON Manuals