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Test F: Compressor Clutch Does Not Engage

WARNING: This page is about a different car, the 2002 Pontiac Sunfire and 2002 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Definition: The A/C compressor clutch will not engage when an A/C request has been made and a Powertrain DTC has not been set.
  1. Perform diagnostic system check. See DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. If diagnostic system check has been performed, go to next step.
  2. Connect scan tool to vehicle DLC. Start engine. Using scan tool, observe Engine Coolant Temperature (ECT) parameter in Powertrain Data list. If scan tool indicates ECT parameter is below 250°F (121°C), go to next step. If scan tool indicates ECT parameter is above 250°F (121°C), repair engine overheating problem.
  3. Ensure outside air temperature is above 36°F (3°C). Start engine. Place blower switch in maximum speed position. Place A/C request switch in ON position. Place air temperature switch in the coldest position. Cycle mode switch through each position except OFF. If A/C compressor operates in each mode position, problem is intermittent. Check wiring harness and connectors for damage or defects and poor connections. If A/C compressor does not operates in each mode position, go to next step.
  4. If A/C compressor operates with mode switch in DEFROST or RECIRCULATION positions, go to next step. If A/C compressor does not operate with mode switch in DEFROST or RECIRCULATION positions, go to step  6.
  5. Place mode switch in VENT position. If A/C compressor operates, go to next step. If A/C compressor does not operate, go to step  19.
  6. Park vehicle inside or in the shade out of direct sunlight. Open windows in order to ventilate interior of vehicle. Turn ignition off. Install manifold gauge set to A/C system. Record outside air temperature. Record readings of low and high side STATIC pressures. Compare the recorded pressure values with specifications for the ambient air temperature. See Figure and Figure . If pressure values are within specification for the ambient air temperature, and within 15 psi (103 kPa) of each other, go to next step. If pressure values are not within specification for the ambient air temperature, and not within 15 psi (103 kPa) of each other, go to LEAK TESTING in GENERAL SERVICING PROCEDURES article in GENERAL SERVICING.
  7. Turn ignition on, with engine off. Using scan tool, observe A/C HIGH SIDE PRESSURE SENSOR parameter in Powertrain Data list. Compare A/C high side pressure on scan tool to high side pressure value on manifold gauge set. If high side pressure values are within 15 psi (1.05 kg/cm2 ) of each other, go to next step. If high side pressure values are not within 15 psi (1.05 kg/cm2 ) of each other, go to step  21.
  8. If the HVAC control assembly is inoperative, go to step  12. If the HVAC control assembly is operative, go to next step.
  9. Start engine. Using scan tool, observe A/C REQUEST parameter in Powertrain Data-2 list. Place blower switch in maximum speed position. Place mode switch in RECIRCULATION position. If scan tool indicates parameter is YES, go to next step. If scan tool does not indicate parameter is YES, go to step  14.
  10. Using scan tool, observe A/C RELAY COMMANDED parameter in Powertrain Data-2 list. If scan tool indicates parameter is ON, go to next step. If scan tool does not indicate parameter is ON, go to step  32.
  11. Using scan tool, command A/C compressor clutch relay ON and OFF. If compressor clutch relay turns ON and OFF with each command, go to step  15. If compressor clutch relay does not turn ON and OFF with each command, go to step  17.
  12. Check ignition voltage circuit to HVAC control assembly for a short to ground, high resistance, or an open. See WIRING DIAGRAMS . If a circuit condition was found, repair as necessary and go to step  39. If a circuit condition was not found, go to next step.
  13. Check ground circuit to HVAC control assembly for an open. See WIRING DIAGRAMS . If an open was found, repair as necessary and go to step  39. If an open was not found, go to step  30.
  14. Start engine. Place mode switch in MAX A/C position. Using a test light connected to ground, probe A/C request signal circuit at BCM. See WIRING DIAGRAMS . If test light illuminates, go to step  31. If test light does not illuminate, go to step  19.
  15. Turn ignition off. Remove compressor clutch relay from underhood fuse block. See Figure. Using a test light connected to ground, probe voltage supply circuit on switch side of the A/C compressor clutch relay. If test light illuminates, go to next step. If test light does not illuminate, go to step  24.
  16. Connect a 10-amp fused jumper wire between voltage circuit on switch side of A/C compressor clutch relay and voltage supply circuit of A/C compressor clutch. See WIRING DIAGRAMS . If compressor clutch engages, go to step  28. If compressor clutch does not engage, go to step  20.
  17. Turn ignition off. Remove compressor clutch relay from underhood fuse block. See Figure. Turn ignition on, with engine off. Using a test light connected to ground, probe voltage supply circuit on coil side of compressor clutch relay. If test light illuminates, go to next step. If test light does not illuminate, go to step  23.
  18. Connect a test light between compressor clutch relay control circuit and voltage supply circuit on coil side of the compressor clutch relay. Using scan tool, command compressor clutch relay ON and OFF. If test light turns ON and OFF with each command, go to step  28. If test light does not turn ON and OFF with each command, go to step  25.
  19. Check A/C request signal circuit for a short to ground, high resistance, or an open. See WIRING DIAGRAMS . If a circuit condition was found, repair as necessary and go to step  39. If a circuit condition was not found, go to step  26.
  20. Check voltage supply circuit to compressor clutch for a short to ground, high resistance, or an open. See WIRING DIAGRAMS . If a circuit condition was found, repair as necessary and go to step  39. If a circuit condition was not found, go to step  22.
  21. Check ground circuit of the A/C refrigerant pressure sensor for an open. See WIRING DIAGRAMS . If an open was found, repair as necessary and go to step  39. If an open was not found, go to step  27.
  22. Check ground circuit of the compressor clutch for high resistance or an open. See WIRING DIAGRAMS . If high resistance or an open was found, repair as necessary and go to step  39. If high resistance or an open was not found, go to step  29.
  23. Repair the voltage supply circuit on coil side of the compressor clutch relay. If repair is complete, go to step  39.
  24. Repair the voltage supply circuit on switch side of the compressor clutch relay. If repair is complete, go to step  39.
  25. Check the control circuit of the compressor clutch relay for an open or a short to voltage. See WIRING DIAGRAMS . If an open or a short to voltage was found, repair as necessary and go to step  39. If an open or a short to voltage was not found, go to step  32.
  26. Check voltage supply circuit to blower motor relay for an open. See WIRING DIAGRAMS . If an open was found, repair as necessary and go to step  39. If an open was not found, go to step  30.
  27. Check harness connector at A/C refrigerant pressure sensor for a poor connection. If a poor connection was found, repair as necessary and go to step  39. If a poor connection was not found, go to step  33.
  28. Check compressor clutch relay for a poor connection in underhood fuse block. If a poor connection was found, repair as necessary and go to step  39. If a poor connection was not found, go to step  34.
  29. Check harness connector at compressor clutch for a poor connection. If a poor connection was found, repair as necessary and go to step  39. If a poor connection was not found, go to step  35.
  30. Check harness connector at HVAC control assembly for a poor connection. If a poor connection was found, repair as necessary and go to step  39. If a poor connection was not found, go to step  36.
  31. Check harness connector at BCM for a poor connection. If a poor connection was found, repair as necessary and go to step  39. If a poor connection was not found, go to step  37.
  32. Check harness connector at PCM for a poor connection. If a poor connection was found, repair as necessary and go to step  39. If a poor connection was not found, go to step  38.
  33. Replace A/C refrigerant pressure sensor. See A/C PRESSURE SENSOR  under REMOVAL & INSTALLATION. After repairs are complete, go to step  39.
  34. Replace compressor clutch relay. See Figure. After repairs are complete, go to step  39.
  35. Replace A/C compressor clutch coil. See COMPRESSOR SERVICING article in GENERAL SERVICING. After repairs are complete, go to step  39.
  36. Replace HVAC control assembly. See HVAC CONTROL ASSEMBLY  under REMOVAL & INSTALLATION. After repairs are complete, go to step  39.
  37. Replace BCM. See appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. After repairs are complete, go to step  39.
  38. Replace and reprogram PCM. See PCM under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION - CAVALIER & SUNFIRE article in ENGINE PERFORMANCE. After repairs are complete, go to step  39.
  39. Operate system to verify repair. If symptom has been corrected, system is okay. If symptom has not been corrected, go to step  4.
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