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Home >> Ford >> 2000 >> Expedition 5.4 L, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1 (A/C-Heater System - Manual) >> Troubleshooting >> Test B: A/C Does Not Operate Or Does Not Operate Properly

Test B: A/C Does Not Operate Or Does Not Operate Properly

WARNING: This page is about a different car, the 1999 Ford Expedition. However, it is still accessible from the selected car via links, so may be relevant.

  1. Check Fuse No. 5 (15-Amp)

    Check fuse No. 5 in instrument panel fuse block. If fuse is okay, go to step 3)  . If fuse is blown, go to next step.

  2. Recheck Fuse No. 5 (15-Amp)

    Replace fuse No. 5. Turn ignition to run (engine off). Check fuse. If fuse blows, go to step 11)  . If fuse is okay, check system operation. If system operates correctly, test is complete. If system does not operate, go to next step.

  3. Check PID WACF With A/C OFF

    Ensure ambient temperature is above 50°F (10°C). Turn ignition to run position (engine off). Turn A/C system off. Perform PCM Parameter Identification WOT A/C Primary Circuit Fault (PID WACF) test. If PID WACF reads YES, perform PCM self-diagnostics test. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE. If PID WACF does not read YES, go to next step.
    NOTE: If PID WACF reads YES, this is the same fault as DTC P1460.

  4. Check PID WACF With A/C ON

    Start engine and run at idle. Set function selector to MAX A/C position. Perform PCM PID WACF. If PID WACF reads YES, perform PCM self-diagnostics test. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE. If PID WACF does not read YES, go to next step.

  5. Check PID ACCS With A/C ON

    Run engine at idle. Set system to MAX A/C position. Perform PCM Parameter Identification A/C Cycling Switch (PID ACCS) input. If PID ACCS reads ON, go to step 11)  . If PID ACCS does not read ON, go to next step.

  6. Check PID ACCS With A/C ON

    Rotate function selector to each switch position. Perform PCM PID ACCS. If PID ACCS reads ON for any switch position, replace function selector switch. If PID ACCS does not read ON, go to next step.

  7. Check Voltage At A/C Cycling Switch

    Turn ignition off. Disconnect A/C cycling switch connector. Turn ignition to run (engine off). Using voltmeter, measure voltage of Red/Yellow wire at cycling switch connector. If voltage is more than 10 volts, go to next step. If voltage is less than 10 volts, go to step 12)  .

  8. Check A/C Cycling Switch

    Perform PCM PID ACCS. Connect jumper wire between Red/Yellow and Black/Yellow wire terminals of cycling switch connector. Turn function selector to MAX A/C position. If PID ACCS reads ON, go, to next step. If PID ACCS does not read ON, go to step 10)  .

  9. Check Black/Yellow Wire Circuit For Open

    Turn ignition off. Disconnect PCM 104-pin Gray harness connector (C174). Connect Breakout Box (014-00950) to PCM wiring harness connector. DO NOT connect to PCM. Using ohmmeter, measure resistance at breakout box pin No. 41. If resistance is less than 5 ohms, replace PCM. Retest system. If resistance is more than 5 ohms, repair Black/Yellow wire. Retest system.

  10. Check Refrigerant System Pressure

    Turn ignition off. Connect manifold gauge set. If refrigerant system pressure is 50-250 psi (3.5-17.6 kg/cm2 ), replace A/C cycling switch. Retest system. If refrigerant system pressure is not 50-250 psi (3.5-17.6 kg/cm2 ), leak test system. Repair as necessary and retest system.

  11. Check PID ACCS With A/C On

    Set system to MAX A/C position. Perform PCM PID ACCS. If PID ACCS reads ON, go to step 25)  . If PID ACCS does not read ON, perform PCM self-diagnostics test. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.

  12. Check Fuse No. 5 (15-Amp)

    Turn ignition off. Disconnect A/C clutch relay connector. Install new fuse in fuse cavity No. 5. Turn ignition to run (engine off). If fuse blows, go to next step. If fuse does not blow, go to step 15)  .

  13. Check Blend Door Actuator

    Turn ignition off. Disconnect blend door actuator connector. Turn function selector to OFF. Measure resistance at breakout box pin No. 41. If resistance is less than 5 ohms, replace PCM. Retest system. If resistance is more than 5 ohms, repair Black/Yellow wire.

  14. Check A/C Clutch Relay

    Turn function selector to MAX A/C position. Check fuse No. 5. If fuse blows, go to step 17)  . If fuse is okay, go to next step.

  15. Check A/C Clutch

    Turn ignition off. Disconnect A/C clutch connector. Measure resistance of Gray/White wire between clutch connector and ground. If resistance is less than 10,000 ohms, go to next step. If resistance is more than 10,000 ohms, replace clutch coil.

  16. Check A/C Clutch Diode

    Disconnect A/C clutch diode connector in battery junction box in engine compartment. Measure resistance of Gray/White wire between A/C clutch relay connector and ground. If resistance is less than 10,000 ohms, repair Gray/White wire. Retest system. If resistance is more than 10,000 ohms, replace A/C clutch diode.

  17. Check Violet Wire Circuit For Short To Ground

    Disconnect A/C pressure cut-off switch connector. Measure resistance of Violet wire between cut-off switch connector and ground. If resistance is less than 10,000 ohms, go to next step. If resistance is more than 10,000 ohms, repair Violet wire. Retest system.

  18. Check Red/Yellow Wire Circuit For Short

    Disconnect A/C cycling switch harness connector. Measure resistance of Red/Yellow wire between cycling switch and ground. If resistance is more than 10,000 ohms, go to next step. If resistance is less than 10,000 ohms, repair short in Red/Yellow wire. Retest system.

  19. Check Red/Yellow Wire Circuit For Open

    Connect pressure cut-off switch connector. Measure resistance of Red/Yellow wire between cycling switch connector and ground. If resistance is less than 10,000 ohms, repair open in Red/Yellow wire. If resistance is more than 10,000 ohms, replace pressure cut-off switch. Retest system.

  20. Check Voltage At Pressure Cut-Off Switch

    Turn ignition off. Disconnect A/C cycling switch connector. Turn function selector to MAX A/C position. Measure voltage of Violet wire between pressure cut-off switch connector and ground. If voltage is more than 10 volts, go to next step. If voltage is less than 10 volts, go to step 22)  .

  21. Check Red/Yellow Wire Circuit For Open

    Turn ignition off. Disconnect A/C cycling switch connector. Measure resistance of Red/Yellow wire between A/C cycling switch connector and pressure cut-off switch connector. If resistance is less than 5 ohms, replace pressure cut-off switch. Retest system. If resistance is more than 5 ohms, repair open in Red/Yellow wire. Retest system.

  22. Check Voltage At Function Selector Switch

    Turn ignition off. Disconnect function selector switch connector. Measure voltage of Light Blue/Pink wire between function selector switch connector and ground. If voltage is more than 10 volts, go to next step. If voltage is less than 10 volts, repair open in Light Blue/Pink wire. Retest system.

  23. Check Violet Wire Circuit For Open

    Disconnect pressure cut-off switch connector. Measure resistance of Violet wire between function selector switch connector and pressure cut-off switch connector. If resistance is less than 5 ohms, replace function selector switch. Retest system. If resistance is more than 5 ohms, repair open in Violet wire. Retest system.

  24. Check Black/Yellow Wire Circuit For Open

    Measure resistance of Black/Yellow wire between breakout box pin No. 41 and pressure cut-off switch. If resistance is less than 5 ohms, replace pressure cut-off switch. If resistance is more than 5 ohms, repair open in Black/Yellow wire.

  25. Check Light Blue/Pink Wire Circuit For Open

    Turn ignition off. Disconnect A/C clutch relay connector. Turn ignition to run (engine off). Measure voltage of Light Blue/Pink wire between clutch relay connector and ground. If voltage is more than 10 volts, go to next step. If voltage is less than 10 volts, repair open in Light Blue/Pink wire. Retest system.

  26. Check A/C Clutch Input

    Turn ignition off. Reconnect A/C clutch relay connector. Disconnect A/C clutch coil connector. Turn ignition to run (engine off). Using New Generation Star Tester (007-00500) in ACTIVE COMMAND MODE, command PCM outputs ON. Measure voltage of Gray/White wire at A/C clutch coil connector. If voltage is more than 10 volts, go to step 28)  . If voltage is less than 10 volts, go to next step.

  27. Check Gray/White Wire Circuit For Open

    Turn ignition off. Disconnect A/C clutch relay connector. Measure resistance of Gray/White wire between clutch relay connector and A/C clutch coil connector. If resistance is less than 5 ohms, replace A/C clutch relay. Retest system. If resistance is more than 5 ohms, repair open in Gray/White wire.

  28. Check A/C Clutch Ground Circuit For Open

    Measure resistance of Black wire between clutch connector and ground. If resistance is one ohm or less, replace A/C clutch coil. Retest system. If resistance is more than one ohm, repair open in Black wire. Retest system.
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