Test G: Compressor Clutch Does Not Disengage

2001 Chevrolet Chevy Express G3500, Van Passenger Extended, 6.5 FSECTION Test G: Compressor Clutch Does Not Disengage
WARNING: This page is about a different car, the 2002 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform diagnostic system check. See DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing system check, go to next step.
  2. Connect scan tool. Turn ignition on. Using scan tool, command A/C relay ON and OFF. If A/C compressor clutch engages and disengages with each command, go to next step. If A/C compressor clutch does not engage and disengage go to step  7.
  3. Start engine. Depress A/C button to OFF position. Using scan tool, observe COMMANDED A/C parameter in POWERTRAIN CONTROL MODULE (PCM) ENGINE data list. If scan tool displays OFF, go to step  12. If scan tool does not display OFF, go to next step.
  4. Use scan tool to observe CONTROL HEAD (DESIRED) parameter in DASH INTEGRATION MODULE (DIM) A/C data list. If scan tool displays A/C OFF, go to next step. If scan tool does not display A/C OFF, go to step  6.
  5. Use scan tool to observe A/C CLUTCH (DESIRED) parameter in DASH INTEGRATION MODULE (DIM) A/C data list. If scan tool displays OFF, go to step  12. If scan tool does not display OFF, go to step  11.
  6. Use scan tool to observe A/C REQUESTED parameter in IPM HVAC SYSTEM data list. If scan tool displays NO, go to step  11. If scan tool does not display NO, go to step  10.
  7. Turn ignition OFF. Disconnect A/C compressor clutch relay. Turn ignition on, engine off. If A/C clutch disengages, go to step  13. If A/C clutch does not disengage, go to next step.
  8. Disconnect A/C compressor. If A/C compressor clutch disengages, go to next step. If A/C clutch does not disengage, go to step  14.
  9. Repair short to voltage in Dark Green wire between terminal "B" of A/C compressor clutch harness connector and terminal C11 of A/C compressor clutch relay socket. Go to step  18.
  10. Check for loose wires and/or poor connections at IPM harness connector, If poor connection is found, repair as necessary. Go to step  18. If poor connection is not found, go to step  15.
  11. Check for loose wires and/or poor connections at DIM harness connector, If poor connection is found, repair as necessary. Go to step  18. If poor connection is not found, go to step  16.
  12. Check for loose wires and/or poor connections at PCM, If poor connection is found, repair as necessary. Go to step  18. If poor connection is not found, go to step  17.
  13. Replace A/C clutch relay. When repair is complete, go to step  18.
  14. Replace A/C Compressor (A/C clutch is not serviceable separately). See COMPRESSOR  under REMOVAL & INSTALLATION. When repair is complete, go to step  18.
  15. Replace IPM. See INSTRUMENT PANEL MODULE (IPM)  under REMOVAL & INSTALLATION. When repair is complete, go to step  18.
  16. Replace DIM. See DASH INTEGRATION MODULE (DIM)  under REMOVAL & INSTALLATION. When repair is complete, go to step  18.
  17. Replace PCM. See POWERTRAIN CONTROL MODULE REMOVAL, OVERHAUL & INSTALLATION article in ENGINE PERFORMANCE. When repair is complete, go to step  18.
  18. Operate system to verify repair. If condition is corrected, system is okay. If condition is not corrected, go to step  2.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.