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Cooling Fan Inoperative

  1. If diagnostic system check has been performed, go to next step. If diagnostic system check has not been performed, see DIAGNOSTIC SYSTEM CHECK .
  2. Install scan tool. Turn ignition on, engine off. Using scan tool, command fans low speed on and off. If low speed engine cooling fans turn on and off with each command, go to next step. If low speed engine cooling fans do not turn on and off with each command, go to step  4.
    3. NOTE: Before PCM changes speed of cooling fan, a 3-second delay will occur.
  3. Using scan tool, command fans high speed on and off. If high speed engine cooling fans turn on and off with each command, problem is intermittent. If high speed cooling fans do not turn on and off with each command, go to step  13.
  4. Check battery voltage circuit for open or short to ground. If problem was found, repair as necessary. After repairs, go to step  35. If problem was not found, go to next step.
  5. Check cooling fan motor supply voltage circuit for short to ground. If problem was found, repair as necessary. After repairs, go to step  35. If problem was not found, go to next step.
    6. NOTE: Following this step, do not remove fused jumper (20-amp) that is connected during this step. While performing the following steps, use a second fused jumper (20-amp).
  6. Disconnect cooling fan 1 relay. Connect first fused jumper (20-amp) between battery positive voltage circuit (Red wire) of cooling fan 1 relay and cooling fan motor supply voltage circuit (Gray wire) of cooling fan 1 relay. If both cooling fans operate in low speed, go to step  15. If both cooling fans do not operate in low speed, go to next step.
  7. Disconnect cooling fan series/parallel relay. Connect second fused jumper (20-amp) between left cooling fan low reference circuit (White wire) of cooling fan series/parallel relay and right cooling fan supply voltage circuit (Light Blue wire) of cooling fan series/parallel relay. If both cooling fans operate in low speed, go to step  16. If both cooling fans do not operate in low speed, go to next step.
  8. Connect second fused jumper (20-amp) between battery voltage and cooling fan motor supply voltage circuit (Light Blue wire) of cooling fan series/parallel relay. If right cooling fan operates in high speed, go to step  11. If right cooling fan does not operate in high speed, go to next step.
  9. Install cooling fan series/parallel relay. Disconnect right cooling fan electrical connector. Connect second fused jumper (20-amp) between terminals of right cooling fan electrical connector. If left cooling fan operates in high speed, go to step  23. If left cooling fan does not operate in high speed, go to next step.
  10. Connect second fused jumper (20-amp) between cooling fan motor supply voltage circuit (Light Blue wire) of right cooling fan electrical connector and ground. If left cooling fan operates in high speed, go to step  27. If left cooling fan does not operate in high speed, go to step  28.
  11. Install cooling fan series/parallel relay. Disconnect left cooling fan electrical connector. Connect second fused jumper (20-amp) between terminals of left cooling fan electrical connector. If right cooling fan operates in high speed, go to step  24. If left cooling fan does not operate in high speed, go to next step.
  12. Connect second fused jumper (20-amp) between battery voltage and left cooling fan low reference circuit (White wire) of left cooling fan electrical connector. If right cooling fan operates in high speed, go to step  25. If left cooling fan does not operate in high speed, go to step  29.
  13. If right cooling fan is operating properly in high speed, go to next step. If right cooling fan is not operating properly in high speed, go to step  19.
  14. Disconnect cooling fan series/parallel relay. Connect second fused jumper (20-amp) between left cooling fan low reference circuit (White wire) of cooling fan series/parallel relay and ground circuit (Black wire) of cooling fan series/parallel relay. If left cooling fan operates properly in high speed, go to step  16. If left cooling fan does not operate properly in high speed, go to step  26.
  15. Check cooling fan 1 relay connector for poor connections. If problem was found, repair as necessary. After repairs, go to step  35. If problem was not found, go to step  30.
  16. Check battery voltage circuit (Orange wire) of cooling fan series/parallel relay for open. If problem was found, repair as necessary. After repairs, go to step  35. If problem was not found, go to next step.
  17. Check high speed cooling fan relay control circuit (Dark Blue wire) of cooling fan series/parallel relay for open. If problem was found, repair as necessary. After repairs, go to step  35. If problem was not found, go to next step.
  18. Check cooling fan series/parallel relay connector for poor connections. If problem was found, repair as necessary. After repairs, go to step  35. If problem was not found, go to step  31.
  19. Check battery voltage circuit (Red wire) of cooling fan 2 relay for open. If problem was found, repair as necessary. After repairs, go to step  35. If problem was not found, go to next step.
  20. Check high speed cooling fan relay control circuit (Dark Blue wire) of cooling fan 2 relay for open. If problem was found, repair as necessary. After repairs, go to step  35. If problem was not found, go to next step.
  21. Check cooling fan motor supply voltage circuit (Light Blue wire) of right cooling fan for open. If problem was found, repair as necessary. After repairs, go to step  35. If problem was not found, go to next step.
  22. Check cooling fan 2 relay connector for poor connections. If problem was found, repair as necessary. After repairs, go to step  35. If problem was not found, go to step  32.
  23. Check right cooling fan connector for poor connections. If problem was found, repair as necessary. After repairs, go to step  35. If problem was not found, go to step  33.
  24. Check left cooling fan connector for poor connections. If problem was found, repair as necessary. After repairs, go to step  35. If problem was not found, go to step  34.
  25. Repair left cooling fan supply voltage circuit (Gray wire). After repairs, go to step  35.
  26. Repair left cooling fan ground circuit (Black wire). After repairs, go to step  35.
  27. Repair right cooling fan ground circuit (Black wire). After repairs, go to step  35.
  28. Repair right cooling fan supply voltage circuit (Light Blue wire). After repairs, go to step  35.
  29. Repair left cooling fan low reference circuit (White wire). After repairs, go to step  35.
  30. Replace cooling fan 1 relay. After repairs, go to step  35.
  31. Replace cooling fan series/parallel relay. After repairs, go to step  35.
  32. Replace cooling fan 2 relay. After repairs, go to step  35.
  33. Replace right cooling fan. After repairs, go to step  35.
  34. Replace left cooling fan. After repairs, go to next step.
  35. Operate system to verify repair.
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