A/C Compressor Clutch Does Not Disengage

WARNING: This page is about a different car, the 2002 GMC Safari and 2002 Chevrolet Astro. 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: The A/C compressor clutch will not disengage when an A/C request has not been made and a Powertrain DTC has not been set.

Did you review DESCRIPTION & OPERATION and perform the necessary inspections? If so, go to next step. If not, see DESCRIPTION , OPERATION and TROUBLE SHOOTING .
Verify that ambient air temperature is greater than 44°F (7°C). Start engine. Ensure blower and mode switches are in OFF position. If A/C compressor clutch is not engaged, problem is intermittent. Check for poor connections or damaged wiring. Repair as necessary. If A/C compressor clutch is engaged, go to next step.
Turn ignition off. Connect scan tool to Data Link Connector (DLC) located under dash, near steering column. Using scan tool, observe A/C REQUEST parameter in POWERTRAIN data list. If scan tool display indicates YES, go to next step. If scan tool does not display YES, go to step 6.
Check Dark Green/White wire between PCM harness connector C2 terminal No. 17 and A/C high pressure cut-out switch harness connector terminal "A" for short to ground. Repair Dark Green/White wire as necessary. After repairs are complete, go to step 17. If wire is okay, go to next step.
Turn ignition off. Disconnect A/C high pressure switch harness connector. Start engine. Using scan tool, observe A/C REQUEST parameter. If scan tool displays YES, go to step 12. If scan tool does not display YES, go to step 11.
Remove A/C compressor clutch relay. If A/C compressor clutch disengages, go to next step. If A/C compressor clutch does not disengage, go to step 9.
Using DVOM, measure resistance between A/C compressor clutch relay harness connector terminals C8 (Orange wire) and D4 (Dark Green wire). If resistance is infinite, go to next step. If resistance is not infinite, go to step 10.
Check Dark Green/White wire between PCM harness connector C2 terminal No. 43 and A/C compressor clutch relay connector terminal C4 for short to ground. Repair Dark Green/White wire as necessary. After repairs are complete, go to step 17. If wire is okay, go to step 12.
Check Dark Green wire between A/C compressor clutch harness connector terminal "B" and A/C compressor clutch relay connector for short to voltage. Repair Dark Green wire as necessary. After repairs are complete, go to step 17. If wire is okay, go to step 14.
Check for poor connections or connector damage at A/C compressor clutch relay connector. Repair or replace as necessary. After repairs are complete, go to step 17. If connections are okay, go to step 13.
Check for poor connections or connector damage at HVAC control assembly harness connector. Repair or replace as necessary. After repairs are complete, go to step 17. If connections are okay, go to step 15.
Check for poor connections or connector damage at PCM harness connector. Repair or replace as necessary. After repairs are complete, go to step 17. If connections are okay, go to step 16.
Replace A/C compressor clutch relay located in underhood relay center. After repairs are complete, go to step 17.
Replace A/C compressor clutch. See COMPRESSOR SERVICING in GENERAL SERVICING PROCEDURES article in GENERAL SERVICING. After repairs are complete, go to step 17.
Replace HVAC control assembly. See HVAC CONTROL ASSEMBLY under REMOVAL & INSTALLATION. After repairs are complete, go to step 17.
Replace PCM. See POWERTRAIN CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION - ASTRO & SAFARI article in ENGINE PERFORMANCE. After repairs, go to next step.
Operate A/C system to verify repair. If A/C system operates normally, repair is complete. If A/C compressor clutch still will not disengage normally, return to step 3.