Test E: Compressor Clutch Does Not Disengage
WARNING: This page is about a different car, the 2002 Buick Regal and 2002 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.
- If diagnostic system check was not performed, go to DIAGNOSTIC SYSTEM CHECK under SELF-DIAGNOSTICS SYSTEM. If diagnostic system check was performed, go to next step.
- Start engine. Place blower motor switch in OFF position. Place A/C switch in OFF position. If A/C compressor operates, go to next step. If A/C compressor does not operate, check wiring systems and connectors for poor connections.
- Using scan tool, observe A/C REQUEST SIGNAL parameter in Powertrain Control Module engine data 2 list. If scan tool indicates A/C REQUEST SIGNAL parameter is YES, go to next step. If scan tool does not indicate A/C REQUEST SIGNAL parameter is YES, go to step 6.
- Check A/C request signal circuit for short to voltage. If a short to voltage is found, repair as necessary. When repair is complete, go to step 17. If short to voltage is not found, go to next step.
- Turn ignition off. Remove A/C Request Signal circuit terminal from HVAC control module. Start engine. Using scan tool, observe A/C REQUEST SIGNAL parameter. If scan tool indicates A/C REQUEST SIGNAL parameter is NO, go to step 12. If scan tool indicates A/C request signal parameter is not NO, go to step 11.
- Remove A/C compressor clutch relay. If A/C compressor clutch turns off, go to next step. If A/C compressor clutch does not turn off, go to step 9.
- Using DVOM, measure resistance between switch side of A/C compressor clutch relay terminals. If resistance measurement equals infinity, go to next step. If resistance measurement does not equal infinity, go to step 10.
- Check A/C compressor clutch relay control circuit for short to ground. See WIRING DIAGRAMS . If a short to ground is found, repair as necessary. When repair is complete, go to step 17. If short to ground is not found, go to step, 12.
- Check A/C compressor clutch supply voltage circuit for short to voltage. See WIRING DIAGRAMS . If a short to voltage is found, repair as necessary. When repair is complete, go to step 17. If short to voltage is not found, go to step, 14.
- Check A/C compressor clutch relay for poor connections. If poor connection is found, repair as necessary. When repair is complete, go to step 17. If poor connection is not found, go to step, 13.
- Check HVAC control module harness connector for poor connections. If poor connection is found, repair as necessary. When repair is complete, go to step 17. If poor connection is not found, go to step 15.
- Check powertrain control module (PCM) harness connector for poor connections. If poor connection is found, repair as necessary. When repair is complete, go to step 17. If poor connection is not found, go to step, 16.
- Replace A/C compressor clutch relay. When repair is complete, go to step 17.
- Replace A/C compressor clutch. Replace compressor and clutch as an assembly. See COMPRESSOR under REMOVAL & INSTALLATION. When repair is complete, go to step 17.
- Replace HVAC control module. See HVAC CONTROL MODULE under REMOVAL & INSTALLATION. When repair is complete, go to step 17.
- Replace PCM. See POWERTRAIN CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION - CENTURY, GRAND PRIX, IMPALA, MONTE CARLO & REGAL article in ENGINE PERFORMANCE. When repair is complete, go to next step.
- Operate system to verify repair. If condition is corrected, system is okay. If condition is not corrected, go to step 4.