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Cooling Fan Inoperative

  1. Did you perform the DIAGNOSTIC SYSTEM CHECK - ENGINE COOLING? If so, go to next step. If not, go to DIAGNOSTIC SYSTEM CHECK - ENGINE COOLING  under SELF-DIAGNOSTIC.
  2. Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, command the FANS LOW SPEED ON and OFF. Do the low speed engine cooling fans turn ON and OFF with each command? If so, go to next step. If not, go to step  4 .
    NOTE: A 3 second delay occurs before the Powertrain Control Module (PCM)/Engine Control Module (ECM) changes the cooling fan speed.
  3. With a scan tool, command the FANS HIGH SPEED ON and OFF. Do the high speed engine cooling fans turn ON and OFF with each command? If so, see INTERMITTENTS  in SYMPTOMS - ENGINE COOLING under TROUBLE SHOOTING. If not, go to step  11 .
    NOTE: DO NOT remove the 20 Amp fused jumper wire connected during this step. Use a second 20 A fused jumper wire while performing the following steps.
  4. Disconnect the cooling fan 1 relay. Connect the first 20-Amp fused jumper between the battery positive voltage circuit of the cooling fan 1 relay and the cooling fan motor supply voltage circuit of the cooling fan 1 relay. Do both cooling fans operate in low speed? If so, go to step  13 . If not, go to next step.
  5. Disconnect the cooling fan s/p relay. Connect the second 20-Amp fused jumper between the left cooling fan motor low reference circuit of the cooling fan 2 relay and the right cooling fan motor supply voltage circuit of the cooling fan 2 relay. Do both cooling fans operate in low speed? If so, go to step  14 . If not, go to next step.
  6. Reconnect the second 20-Amp fused jumper between the battery positive voltage circuit of the cooling fan 2 relay and the cooling fan motor supply voltage circuit of the cooling fan 2 relay. Does the right cooling fan operate in high speed? If so, go to step  9 . If not, go to next step.
  7. Install the cooling fan 2 relay. Disconnect the right cooling fan electrical connector. Reconnect the second 20-Amp fused jumper wire from the cooling fan motor supply voltage circuit of the right cooling fan electrical connector to the cooling fan motor ground circuit of the right cooling fan electrical connector. Does the left cooling fan operate in high speed? If so, go to step  16 . If not, go to next step.
  8. Reconnect the second 20-Amp fused jumper wire from the cooling fan motor supply voltage circuit of the right cooling fan electrical connector to a good ground. Does the left cooling fan operate in high speed? If so, go to step  20 . If not, go to step  21 .
  9. Install the cooling fan 2 relay. Disconnect the left cooling fan electrical connector. Reconnect the second 20-Amp fused jumper wire from cooling fan motor supply voltage circuit of the left cooling fan electrical connector to the cooling fan low reference circuit of the left cooling fan electrical connector. Does the right cooling fan operate in high speed? If so, go to step  17 . If not, go to next step.
  10. Reconnect the second 20-Amp fused jumper wire from battery positive voltage to the left cooling fan low reference circuit of the of the left cooling fan electrical connector. Does the right cooling fan operate in high speed? If so, go to step  18 . If not, go to step  22 .
  11. Does the right cooling fan operate in high speed? If so, go to next step. If not, go to step  15 .
  12. Disconnect the cooling fan 2 relay. Connect a 20-Amp fused jumper between the left cooling fan low reference circuit of the cooling fan 2 relay and the ground circuit of the cooling fan 2 relay. Does the left cooling fan operate properly in high speed? If so, go to step  14 . If not, go to step  19 .
  13. Inspect for poor connections at the cooling fan 1 relay. Did you find and correct the condition? If so, go to step  28 . If not, go to step  23 .
  14. Inspect for poor connections at the cooling fan 2 relay. Did you find and correct the condition? If so, go to step  28 . If not, go to step  24 .
  15. Inspect for poor connections at the cooling fan 3 or S/P relay. Did you find and correct the condition? If so, go to step  28 . If not, go to step  25 .
  16. Inspect for poor connections at the harness connector of the right cooling fan. Did you find and correct the condition? If so, go to step  28 . If not, go to next step.
  17. Inspect for poor connections at the harness connector of the left cooling fan. Did you find and correct the condition? If so, go to step  28 . If not, go to next step.
  18. Repair the left cooling fan motor supply voltage circuit. After repairs are complete, go to step  28 .
  19. Repair the left cooling fan motor ground circuit. After repairs are complete, go to step  28 .
  20. Repair the right cooling fan motor ground circuit. After repairs are complete, go to step  28 .
  21. Repair the right cooling fan motor supply voltage circuit. Did you complete the repair? After repairs are complete, go to step  28 .
  22. Repair the left cooling fan low reference circuit. After repairs are complete, go to step  28 .
  23. Replace the cooling fan 1 relay. After replacement is complete, go to step  28 .
  24. Replace the cooling fan 2 relay. After replacement is complete, go to step  28 .
  25. Replace the cooling fan 3 or S/P relay. After replacement is complete, go to step  28 .
  26. Replace the right cooling fan. See COOLING FAN MOTOR  under REMOVAL & INSTALLATION. After replacement is complete, go to step  28 .
  27. Replace the left cooling fan. See COOLING FAN MOTOR  under REMOVAL & INSTALLATION. After replacement is complete, go to next step.
  28. Operate the system in order to verify the repair. Did you correct the condition? If so, then system is okay. If system is not okay, go to step  3 .
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