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Test G: Compressor Clutch Does Not Engage

WARNING: This page is about a different car, the 2002 Oldsmobile Intrigue. 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 engage when an A/C request has been made and a Powertrain DTC has not been set.
  1. If diagnostic system check was not performed, go to If diagnostic system check was not performed, go to DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. If diagnostic system check was performed, go to next step. If diagnostic system check was performed, go to next step.
  2. Install a scan tool. Start the engine. With a scan tool, observe the ENGINE COOLANT TEMPERATURE SENSOR (ECT) parameter in the Powertrain Data list. Does the scan tool indicate that the ECT parameter is above 255°F (124°C)? If so, check for cause of engine overheating. If not, go to next step.
  3. For A/C compressor operation, ambient air temperature must be above 38°F (3°C). Start the engine. Place the blower motor switch in the maximum speed position. Place the A/C request switch in the ON position. Place the air temperature switch in the coldest position. Does the A/C compressor operate? If so, problem is intermittent. If not, go to next step.
  4. Park the vehicle inside or in the shade. Open the windows in order to ventilate the interior of the vehicle. If the A/C system was operating, then allow the A/C system to equalize for approximately 2 minutes. Ensure that the ignition key is in the OFF position. Install the ACR 2000 Air Conditioning Service Center. Record the ambient air temperature at the vehicle. Record readings of the low and high side static pressures. Compare the low and high side pressure values with the allowable limits for the recorded ambient air temperature. See A/C SYSTEM PERFORMANCE TEST under PERFORMANCE TESTS in INTRIGUE article in MANUAL A/C-HEATER SYSTEMS. Are the low and high side pressure values within the allowable limits for the recorded ambient air temperature, and within 15 psi (103 kPa) of each other? If so, go to next step. If not, check for refrigerant leak. See LEAK TESTING in GENERAL SERVICING PROCEDURES article in GENERAL SERVICING.
  5. Turn ignition on. With a scan tool, observe the A/C HIGH SIDE PRESSURE SENSOR parameter in the Powertrain Control Module engine data 2 list. Compare the A/C high side pressure on the scan tool to the high side pressure value on the ACR 2000. Are the high side pressure values within the 15 psi (103 kPa) of each other? If so, go to next step. If not, go to step  16.
  6. The HVAC control module is inoperative when the module does not respond to any operator control requests. Is the HVAC control module inoperative? If so, go to step  15. If not, go to next step.
  7. Start the engine. With a scan tool, observe the A/C REQUEST SIGNAL parameter in the Powertrain Control Module engine data 2 list. Place the air temperature switch in the coldest position. Place the A/C request switch in the ON position. Does the scan tool indicate that the A/C REQUEST SIGNAL parameter is YES? If so, go to next step. If not, go to step  27.
  8. With a scan tool, observe the A/C RELAY COMMAND status in the powertrain control module data list. Does the scan tool indicate that the A/C RELAY COMMAND status is ON? If so, go to next step. If not, go to step  28.
  9. With a scan tool, command the A/C Relay ON and OFF. Does the A/C compressor clutch relay turn ON and OFF with each command? If so, go to step  13. If not, go to next step.
  10. Turn ignition off. Disconnect the A/C compressor clutch relay. Turn ignition on. Probe the coil side battery positive voltage circuit of the A/C compressor clutch relay with a test light that is connected to ground. Does the test light illuminate? If so, go to next step. If not, go to step  23.
  11. Connect a test light between the A/C compressor clutch relay control circuit of the A/C compressor clutch relay and the coil side battery positive voltage circuit of the A/C compressor clutch relay. With a scan tool, command the A/C Relay ON and OFF. Does the test light turn ON and OFF with each command? If so, go to step  25. If not, go to next step.
  12. Does the test light remain illuminated with each command? If so, go to step  19. If not, go to step  18.
  13. Turn ignition off. Disconnect the A/C compressor clutch relay. Probe the switch side battery positive voltage circuit of the A/C compressor clutch relay with a test light that is connected to ground. Does the test light illuminate? If so, go to next step. If not, go to step  22.
  14. Connect a 10 amp fused jumper wire between the switch side battery positive voltage circuit of the A/C compressor clutch relay and the A/C compressor clutch supply voltage circuit of the A/C compressor clutch. Does the A/C compressor clutch engage? If so, go to step  25. If not, go to step  20.
  15. Check the ignition 3 voltage circuit of the HVAC control assembly for a short to ground, a high resistance, or an open. Did you find and correct the condition? If so, go to step  34. If not, go to step  17.
  16. Check the ground circuit of the A/C refrigerant pressure sensor for an open. Did you find and correct the condition? If so, go to step  34. If not, go to step  24.
  17. Check the ground circuit of the HVAC control module for an open. Did you find and correct the condition? If so, go to step  34. If not, go to step  27.
  18. Check the A/C compressor clutch relay control circuit of the A/C compressor clutch relay for an open. Did you find and correct the condition? If so, go to step  34. If not, go to step  28.
  19. Check the A/C compressor clutch relay control circuit of the A/C compressor clutch relay for a short to ground. Did you find and correct the condition? If so, go to step  34. If not, go to step  28.
  20. Check the A/C compressor clutch supply voltage circuit at the A/C compressor clutch for a short to ground, a high resistance, or an open. Did you find and correct the condition? If so, go to step  34. If not, go to next step.
  21. Check the ground circuit of the A/C compressor clutch for a high resistance or an open. Did you find and correct the condition? If so, go to step  34. If not, go to step  26.
  22. Repair the switch side battery positive voltage circuit of the A/C compressor clutch relay. After repairs are complete, go to step  34.
  23. Repair the coil side battery positive voltage circuit of the A/C compressor clutch relay. After repairs are complete, go to step  34.
  24. Inspect the A/C refrigerant pressure sensor for poor connections. Did you find and correct the condition? If so, go to step  34. If not, go to step  29.
  25. Inspect the A/C compressor clutch relay for poor connections. Did you find and correct the condition? If so, go to step  34. If not, go to step  30.
  26. Inspect the A/C compressor clutch for poor connections. Did you find and correct the condition? If so, go to step  34. If not, go to step  3.
  27. Inspect the HVAC control module for poor connections. Did you find and correct the condition? If so, go to step  34. If not, go to step  32.
  28. Inspect the harness connector of the Powertrain Control Module (PCM) for poor connections. Did you find and correct the condition? If so, go to step  34. If not, go to step  33.
  29. Replace the A/C refrigerant pressure sensor. See A/C PRESSURE SENSOR under REMOVAL & INSTALLATION in INTRIGUE article in MANUAL A/C-HEATER SYSTEMS. After repairs are complete, go to step  34.
  30. Replace the A/C compressor clutch relay. See COMPRESSOR RELAY under REMOVAL & INSTALLATION in INTRIGUE article in MANUAL A/C-HEATER SYSTEMS. After repairs are complete, go to step  34.
  31. Replace the A/C compressor clutch. See COMPRESSOR SERVICING article in GENERAL SERVICING. After repairs are complete, go to step  34.
  32. Replace the HVAC control module. See HVAC CONTROL MODULE  in REMOVAL & INSTALLATION. After repairs are complete, go to step  34.
  33. Replace the PCM. See POWERTRAIN CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION - AURORA & INTRIGUE article in ENGINE PERFORMANCE. After repairs are complete, go to next step.
  34. Operate the system in order to verify the repair. Did you correct the condition? If so, system is okay. If not, go to step  4.
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