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Home >> Pontiac >> 2001 >> Aztek Base, AWD >> Repair and Diagnosis >> Engine Mechanical >> Cooling Fan >> Electric Cooling Fan >> Electric Cooling Fan Circuit Diagnosis >> 3.4L "A" & "B" Series Trucks (AZTEK) >> Cooling Fan Inoperative

Cooling Fan Inoperative

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