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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> Heating, Ventilation & A/C (HVAC) >> HVAC Control Systems >> HVAC Systems - Manual >> Symptom Tests >> Test A: A/C Compressor Clutch Does Not Engage >> 2.2L Engine

2.2L Engine

  1. Perform DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After check is complete, go to next step.
  2. Install scan tool. Start engine. Using scan tool, observe Engine Coolant Temperature (ECT) parameter in Powertrain Data List. If scan tool indicates ECT parameter is greater than 275°F (125°C), check engine for overheating condition. Repair as necessary. If scan tool indicates ECT parameter is less than 275°F (125°C), go to next step.
    3. NOTE: Ambient (outside) air temperature must be greater than 38°F (3°C).
  3. Start engine. Place blower motor switch in maximum speed position. Press A/C switch to ON position. Place air temperature switch in coldest position. If A/C compressor operates, problem is intermittent. Check wiring and connections. If A/C compressor does not operate, go to next step.
  4. Park vehicle out of direct sunlight. Open windows to ventilate interior of vehicle. Allow A/C system to equalize for approximately 2 minutes. Turn ignition off. Install manifold gauge set. Record ambient air temperature at vehicle. Record readings of low and high side STATIC pressures. Compare low and high side pressure values with allowable limits for the recorded ambient air temperature. See A/C PERFORMANCE TEST  under PERFORMANCE TESTS. If low and high side pressure values are within allowable limits for recorded ambient air temperature, and within 15 psi (1.1 kg/cm2 ) of each other, go to next step. If low and high side pressure values are within allowable limits for recorded ambient air temperature, and/or are not within 15 psi (1.1 kg/cm2 ) of each other, leak test vehicle. See LEAK TESTING in GENERAL SERVICING PROCEDURES article in GENERAL SERVICING.
  5. Turn ignition on. Using scan tool, observe A/C HIGH SIDE PRESSURE parameter in Powertrain Data List. Compare A/C high side pressure on scan tool to high side pressure on manifold gauge set. If high side pressure values are within 15 psi (1.1 kg/cm2 ) of each other, go to next step. If high side pressure values are not within 15 psi (1.1 kg/cm2 ) of each other, go to step  19.
  6. If HVAC control module is inoperative, go to step  18. If HVAC control module is operative, go to next step.
  7. Start engine. Using scan tool, observe A/C REQUEST SIGNAL parameter in Powertrain Data List. Place air temperature switch in coldest position. Place mode switch in bi-level position. If scan tool indicates A/C REQUEST SIGNAL parameter is YES, go to next step. If scan tool indicates A/C REQUEST SIGNAL parameter is NO, go to step  30.
  8. Using scan tool, observe A/C HIGH SIDE PRESSURE parameter in Powertrain Data List. If scan tool indicates A/C HIGH SIDE PRESSURE parameter is within 45-425 psi (3.2-29.9 kg/cm2 ), go to step  12. If scan tool indicates A/C HIGH SIDE PRESSURE parameter is not within 45-425 psi (3.2-29.9 kg/cm2 ), go to next step.
  9. Turn ignition off. Disconnect A/C refrigerant pressure sensor. Start engine. Using scan tool, observe A/C HIGH SIDE PRESSURE parameter. If scan tool indicates A/C HIGH SIDE PRESSURE parameter is greater than 425 psi (3.2 kg/cm2 ), go to next step. If scan tool indicates A/C HIGH SIDE PRESSURE parameter is less than 425 psi (3.2 kg/cm2 ), go to step  23.
  10. Turn ignition off. Connect a 3-amp fused jumper wire between A/C refrigerant pressure sensor signal circuit and low reference circuit. Start engine. Using scan tool, observe A/C HIGH SIDE PRESSURE parameter. If scan tool indicates A/C HIGH SIDE PRESSURE parameter is less than 45 psi (3.2 kg/cm2 ), go to next step. If scan tool indicates A/C HIGH SIDE PRESSURE parameter is greater than 45 psi (3.2 kg/cm2 ), go to step  24.
  11. Turn ignition off. Disconnect fused jumper wire. Connect a 3-amp fused jumper wire between A/C refrigerant pressure sensor 5-volt reference circuit and signal circuit. Start engine. Using scan tool, observe A/C HIGH SIDE PRESSURE parameter. If scan tool indicates A/C REFRIGERANT PRESSURE SENSOR parameter is greater than 425 psi (3.2 kg/cm2 ), go to step  22. If scan tool indicates A/C REFRIGERANT PRESSURE SENSOR parameter is less than 425 psi (3.2 kg/cm2 ), go to step  21.
  12. Using scan tool, command A/C Relay ON and OFF. If A/C compressor clutch relay turns ON and OFF with each command, go to step  16. If A/C compressor clutch relay does not turn ON and OFF with each command, go to next step.
  13. Turn ignition off. Disconnect A/C compressor clutch relay. Turn ignition on. Probe coil side voltage supply circuit of A/C relay with test light connected to ground. If test light illuminates, go to next step. If test light does not illuminate, go to step  32.
  14. Connect test light between A/C compressor clutch relay control circuit and coil side voltage supply circuit. Using scan tool, command A/C compressor clutch relay ON and OFF. If test light turns ON and OFF with each command, go to step  33. If test light does not turn ON and OFF with each command, go to next step.
  15. If test light remains illuminated with each command, go to step  27. If test light does not remain illuminated with each command, go to step  26.
  16. Turn ignition off. Disconnect A/C compressor clutch relay. Probe A/C compressor clutch relay switch side voltage supply circuit with test light connected to ground. If test light illuminates, go to next step. If test light does not illuminate, go to step  31.
  17. Connect a 10-amp fused jumper wire between switch side voltage circuit of A/C compressor clutch relay and A/C compressor clutch supply voltage circuit of A/C compressor clutch. If A/C compressor clutch engages, go to step  33. If A/C compressor clutch does not engage, go to step  28.
  18. Check HVAC control assembly ignition voltage circuit for a short to ground, a high resistance, or an open. Repair circuit as necessary, then go to step  43. If circuit is okay, go to step  20.
  19. Check A/C pressure sensor ground circuit for an open. Repair circuit as necessary, then go to step  43. If circuit is okay, go to step  34.
  20. Check HVAC control assembly ground circuit for an open. Repair circuit as necessary, then go to step  43. If circuit is okay, go to step  36.
  21. Check A/C refrigerant pressure sensor 5-volt reference circuit for a short to ground. Repair circuit as necessary, then go to step  43. If circuit is okay, go to step  37.
  22. Check A/C refrigerant pressure sensor 5-volt reference circuit for a short to voltage, a high resistance, or an open. Repair circuit as necessary, then go to step  43. If circuit is okay, go to step  34.
  23. Check A/C refrigerant pressure sensor signal circuit for a short to ground. Repair circuit as necessary, then go to step  43. If circuit is okay, go to step  37.
  24. Check A/C refrigerant pressure sensor signal circuit for a short to voltage, a high resistance, or an open. Repair circuit as necessary, then go to step  43. If circuit is okay, go to next step.
  25. Check A/C refrigerant pressure sensor low reference circuit for a high resistance or an open. Repair circuit as necessary, then go to step  43. If circuit is okay, go to step  37.
  26. Check A/C compressor clutch relay control circuit for an open. Repair circuit as necessary, then go to step  43. If circuit is okay, go to step  37.
  27. Check A/C compressor clutch relay control circuit for a short to ground. Repair circuit as necessary, then go to step  43. If circuit is okay, go to step  37.
  28. Check A/C compressor clutch supply voltage circuit of A/C compressor clutch for a short to ground, a high resistance, or an open. Repair circuit as necessary, then go to step  43. If circuit is okay, go to next step.
  29. Check A/C compressor clutch ground circuit for a high resistance or an open. Repair circuit as necessary, then go to step  43. If circuit is okay, go to step  35.
  30. Turn ignition off. Check A/C request signal circuit for a short to ground, a high resistance, or an open. Repair circuit as necessary, then go to step  43. If circuit is okay, go to step  37.
  31. Repair A/C compressor clutch relay switch side voltage supply circuit. After repairs are complete, go to step  43.
  32. Repair A/C compressor clutch relay coil side voltage supply circuit. After repairs are complete, go to step  43.
  33. Check A/C compressor clutch relay for loose wires and/or poor connections. Repair as necessary, then go to step  43. If wiring and connections are okay, go to step  39.
  34. Check A/C refrigerant pressure sensor harness connector for loose wires and/or poor connections. Repair as necessary, then go to step  43. If wiring and connections are okay, go to step  38.
  35. Check A/C compressor clutch harness connector for loose wires and/or poor connections. Repair as necessary, then go to step  43. If wiring and connections are okay, go to step  40.
  36. Check HVAC control module harness connector for loose wires and/or poor connections. Repair as necessary, then go to step  43. If wiring and connections are okay, go to step  41.
  37. Check PCM harness connector for loose wires and/or poor connections. Repair as necessary, then go to step  43. If wiring and connections are okay, go to step  42.
  38. Replace A/C refrigerant pressure sensor. See PRESSURE SWITCHES  under REMOVAL & INSTALLATION. After replacement, go to step  43.
  39. Replace A/C compressor clutch relay. See COMPRESSOR RELAY  under REMOVAL & INSTALLATION. After replacement, go to step  43.
  40. Replace A/C compressor clutch coil. See COMPRESSOR SERVICING article in GENERAL SERVICING. After replacement, go to step  43.
  41. Replace HVAC control assembly. See HVAC CONTROL ASSEMBLY  under REMOVAL & INSTALLATION. After replacement, go to step  43.
  42. Replace and reprogram PCM. See POWERTRAIN CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION - BLAZER (JIMMY CANADIAN), SONOMA & S10 PICKUP article in ENGINE PERFORMANCE. After replacement, go to next step.
  43. Operate system to verify repair. If system does not operate properly, go to step  4. If system operates correctly, test is complete.
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