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Test J: Compressor Clutch Does Not Disengage

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  1. Perform SYMPTOM DIAGNOSIS  under TROUBLESHOOTING. After test is complete, go to next step.
    2. NOTE: These actions will disable the HVAC control assembly output to Powertrain Control Module (PCM).
  2. Start the engine. Place the blower motor switch in the OFF position. Place the A/C request switch in the OFF position. Does the A/C compressor operate? If so, go to next step. If not, check for intermittent and poor connections.
    3. NOTE: If the A/C Request Signal is NO then the A/C request signal circuits and A/C high pressure switch are functioning normally.
  3. With a scan tool, observe the A/C REQUEST SIGNAL parameter in the Powertrain Data List. Does the scan tool indicate that the A/C REQUEST SIGNAL parameter is YES? If so, go to next step. If not, go to step  6.
    4. NOTE: Ensure that both A/C request signal circuits of the A/C high pressure switch are tested for listed conditions.
  4. Check the A/C request signal circuit for a short to ground. Did you find and correct the condition? If so, go to  17 step. If not, go to next step.
    5. NOTE: The A/C REQUEST SIGNAL parameter is YES. The A/C request signal circuits both are not shorted to ground. This step verifies that the A/C high pressure switch is not shorted internally to ground.
  5. Turn ignition off. Disconnect the A/C high pressure switch. Start the engine. With a scan tool, observe the A/C REQUEST SIGNAL parameter. Does the scan tool indicate that the A/C REQUEST SIGNAL parameter is YES? If so, go to step  12. If not, go to step  11.
  6. Remove the A/C compressor clutch relay. See COMPRESSOR RELAY  under REMOVAL & INSTALLATION. Does the A/C compressor clutch turn off? If so, go to next step. If not, go to step  9.
  7. Measure the resistance between the switched terminals on the A/C compressor clutch relay. Does the resistance measurement equal infinity? If so, go to next step. If not, go to step  10.
  8. Check the control circuit of the A/C compressor clutch relay for a short to ground. Did you find and correct the condition? If so, go to step  17. If not, go to step  12.
  9. Check the A/C compressor clutch supply voltage circuit for a short to voltage. Did you find and correct the condition? If so, go to step  17. If not, go to step  14.
  10. Inspect A/C compressor clutch relay for poor connections. Did you find and correct the condition? If so, go to step  17. If not, go to step  13.
  11. Inspect HVAC control assembly harness connector for poor connections. Did you find and correct the condition? If so, go to step  17. If not, go to step  15.
  12. Inspect Powertrain Control Module (PCM) harness connector for poor connections. Did you find and correct the condition? If so, go to step  17. If not, go to step  16.
  13. Replace the A/C compressor clutch relay. See COMPRESSOR RELAY  under REMOVAL & INSTALLATION. After repairs are complete, go to step  17.
  14. Replace the A/C compressor clutch. See COMPRESSOR SERVICING article in GENERAL SERVICING. After repairs are complete, go to step  17.
    15. NOTE:
  15. Replace the HVAC control assembly. See HVAC CONTROL ASSEMBLY  under REMOVAL & INSTALLATION. Perform the calibration procedure for the HVAC control assembly. After repairs are complete, go to step  17.
  16. Replace the PCM. See POWERTRAIN CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article in ENGINE PERFORMANCE. Program the PCM. After repairs are complete, go to next step.
  17. Operate the system in order to verify the repair. Did you correct the condition? If so, system is okay. If not, go to step  3.
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