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Test K: Compressor Clutch Does Not Disengage

WARNING: This page is about a different car, the 2002 GMC Savana Special, 2002 GMC Savana Camper Special, 2002 GMC Savana, and 2002 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: For circuit reference, see CONNECTOR IDENTIFICATION  and/or WIRING DIAGRAMS  .
NOTE: Definition: A/C compressor clutch will not disengage when an A/C request has been made and a powertrain DTC has not been set.
  1. If review of system operation has been performed, go to next step. If review of system operation has not been performed, see DESCRIPTION  and OPERATION  . Review HVAC operation and perform visual inspection of system. See OPERATION . If system inspection and review of operation has been performed, go to next step.
  2. Start engine. Place blower switch in OFF position. Place A/C request switch in OFF position. If compressor operates, go to next step. If compressor does not operate, problem is intermittent. Check wiring harness and connectors for damage or defects.
  3. Connect scan tool to vehicle DLC. Using scan tool, observe A/C REQUEST SIGNAL parameter in engine data 2 list (except 6.5L), or in engine data 1 list (6.5L). If scan tool indicates A/C REQUEST SIGNAL is YES, go to next step. If scan tool does not indicate YES, go to step  6.
  4. Check A/C request signal circuit (Dark Green/White wire and Light green wire) between PCM, refrigerant pressure switches and HVAC control assembly for a short to voltage. See WIRING DIAGRAMS . If a short to voltage was found, repair as necessary and go to step  17. If a short to voltage was not found, go to next step.
  5. Turn ignition off. Disconnect A/C high pressure switch. Start engine. Using scan tool, observe A/C REQUEST SIGNAL parameter. If scan tool indicates YES, go to step  12. If scan tool does not indicate YES, go to step  11.
  6. Remove compressor clutch relay from underhood fuse block. See Fig 1. If compressor clutch disengages, go to next step. If compressor clutch does not disengage, go to step  9
    Fig 1: Identifying Compressor Clutch Relay
    G00067644Courtesy of GENERAL MOTORS CORP.
  7. Using an ohmmeter, measure resistance between compressor clutch relay terminals No. C1 and D1 (Dark Green wires) at underhood fuse block. See WIRING DIAGRAMS . If resistance is infinity, go to next step. If resistance is not infinity, go to step  10.
  8. Check compressor clutch relay control circuit (Dark Green wire) for a short to ground. See WIRING DIAGRAMS . If a short to ground was found, repair as necessary and go to step  17. If a short to ground was not found, go to step  12.
  9. Check compressor clutch voltage supply circuit (Dark Green wire) for a short to voltage. See WIRING DIAGRAMS . If a short to voltage was found, repair as necessary and go to step  17. If a short to voltage was not found, go to step  14.
  10. Check harness connector at compressor clutch relay for a poor connection. If a poor connection was found, repair as necessary and go to step  17. If a poor connection was not found, go to step  13.
  11. Check harness connector at main HVAC control assembly for a poor connection. If a poor connection was found, repair as necessary and go to step  17. If a poor connection was not found, go to step  15.
  12. Check harness connector at PCM for a poor connection. If a poor connection was found, repair as necessary and go to step  17. If a poor connection was not found, go to step  16.
  13. Replace compressor clutch relay. See Fig 1. After repairs are complete, go to step  17.
  14. Replace compressor clutch. After repairs are complete, go to step  17.
  15. Replace main HVAC control assembly. See MAIN HVAC CONTROL ASSEMBLY  under REMOVAL & INSTALLATION. After repairs are complete, go to step  17.
  16. Replace and program PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article in ENGINE PERFORMANCE. If replacement is complete, go to next step.
  17. Operate system to verify repair. If the condition was corrected, system is okay. If the condition was not corrected, return to step  3.
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