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A/C Compressor Clutch Does Not Engage: Diesel

  1. Ensure A/C system has sufficient refrigerant charge. If refrigerant charge is sufficient, go to next step. If refrigerant charge is not sufficient, see CHARGING A/C SYSTEM in GENERAL SERVICING PROCEDURES article.
  2. Disconnect PCM connector C3. Connect fused jumper wire between VCM connector C3 terminal D5 (Dark Green/White wire) and ground. Turn ignition switch to ON position. If audible click from A/C compressor clutch is heard, go to step  14. If audible click from A/C compressor clutch is not heard, go to next step.
  3. Remove A/C compressor clutch relay. Connect fused jumper wire between A/C compressor clutch relay connector terminals B4 (Orange wire) and A6 (Dark Green wire). If clutch engages, go to next step. If clutch does not engage, go to step  7.
  4. Disconnect PCM connector C3. Connect fused jumper wire between A/C compressor clutch relay terminals A4 (Pink wire) and B6 (Dark Green/White wire). Using DVOM, measure voltage between PCM connector C3 terminal D5 (Dark Green/White wire) and ground. Turn ignition switch to ON position. If battery voltage is present, go to next step. If battery voltage is not present, go to step  6.
  5. Replace A/C compressor clutch relay. After repairs, recheck system operation.
  6. Repair open in Dark Green wire between underhood fuse block and PCM. After repairs, recheck system operation.
  7. Disconnect A/C compressor clutch connector. Using DVOM, check continuity between A/C compressor clutch connector terminal "A" (Black wire) and ground. If continuity exists, go to step  9. If continuity does not exist, go to next step.
  8. Repair open in Black wire between compressor clutch and ground. After repairs, recheck system operation.
  9. Connect fused jumper wire between A/C compressor clutch relay connector terminals B4 (Orange wire) and A6 (Dark Green wire). Using DVOM, measure voltage between terminals of compressor clutch connector. If battery voltage is present, go to step  11. If battery voltage is not present, go to next step.
  10. Repair open in Dark Green wire between underhood fuse block and compressor clutch connector. After repairs, recheck system operation.
  11. Remove fused jumper wire at A/C compressor clutch relay connector. Using DVOM, check continuity between compressor clutch connector terminals. Reverse meter leads at connector and check continuity again. If continuity is present in one direction only, go to step  13. If continuity is not present in one direction only, go to next step.
  12. Replace diode located within A/C compressor clutch harness. After repairs, recheck system operation.
  13. Replace A/C compressor clutch. See appropriate COMPRESSOR SERVICING article in GENERAL SERVICING. After repairs, recheck system operation.
  14. Disconnect A/C compressor cycling switch. Connect jumper between A/C compressor cycling switch connector terminals. Using DVOM, measure voltage between PCM connector C1 terminal C2 (Dark Green wire) and ground. Turn ignition switch to ON position. Turn front blower switch to any position except OFF. Push in A/C Button. If battery voltage is present, go to next step. If battery voltage is not present, go to step  16.
  15. Replace A/C compressor cycling switch. After repairs, recheck system operation.
  16. Disconnect A/C high pressure switch connector. Connect fused jumper wire between A/C high pressure switch connectors. Using DVOM, measure voltage between PCM connector C1 terminal C2 (Dark Green wire) and ground. Turn ignition switch to ON position. Turn front blower switch to any position except OFF. Push in A/C Button. If battery voltage is present, go to next step. If battery voltage is not present, go to step  18.
  17. Replace A/C high pressure switch. After repairs, recheck system operation.
  18. Disconnect HVAC control module connector C3. Connect fused jumper between HVAC control module connector C3 terminals No. 5 (Brown wire) and No. 10 (Light Green wire). Using DVOM, measure voltage between PCM connector C1 terminal C2 (Dark Green/White) and ground. Turn ignition switch to ON position. Turn front blower switch to any position except OFF. Push in A/C Button. If battery voltage is present, go to next step. If battery voltage is not present, go to step  20.
  19. Replace HVAC control module. See A/C-HEATER CONTROL ASSEMBLY  under REMOVAL & INSTALLATION. After repairs, recheck system operation.
  20. Repair open in Brown wire, Light Green wire, Dark Green wire or Dark Green/White wire between instrument panel fuse block and PCM. After repairs, recheck system operation.
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