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Test C: Auxiliary Blower Motor Malfunction

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2002 GMC Savana Special, 2002 GMC Savana Camper Special, 2002 GMC Savana, 2002 Chevrolet RV Cutaway, and 2002 Chevrolet Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: The blower motor operates in at least one, but not all, speed positions.
NOTE: For circuit reference, see CONNECTOR IDENTIFICATION  and/or WIRING DIAGRAMS  .
NOTE: The manufacturer does not separate testing by "heater only" or "air conditioned" vehicles. References to air conditioning operations or repairs may not apply to vehicles without air conditioning. References to some components also may not apply to vehicles without air conditioning.
NOTE: Definition: The auxiliary blower motor operates in at least one, but not all, speed positions.
  1. Did you review the DESCRIPTION  and OPERATION  and perform the necessary inspections? If so, go to next step. If not, go to DESCRIPTION  and OPERATION  , then go to next step.
  2. Turn the ignition on, with the engine off. Place the front auxiliary blower motor switch in each speed position. Does the auxiliary blower motor operate properly in each speed position? If so, go to next step. If not, go to step  5.
  3. Is the vehicle equipped with both front and rear auxiliary HVAC control assemblies? If so, go to next step. If not, condition is intermittent. See TROUBLE SHOOTING .
  4. Place the front auxiliary blower motor switch in the rear control position. Place the rear auxiliary blower motor switch in each speed position. Does the auxiliary blower motor operate properly in each speed position? If so, see TROUBLE SHOOTING . If not, go to step  13.
  5. Turn the ignition off. Disconnect the auxiliary blower motor. Turn the ignition on, with the engine off. Connect a test light between the auxiliary blower motor supply voltage circuit and ground. Place the front auxiliary blower motor switch in each speed position. Does the test light illuminate in each speed position? If so, go to step  12. If not, go to next step.
  6. Turn the ignition off. Disconnect the auxiliary blower motor resistor assembly. Turn the ignition on, with the engine off. Probe each circuit of the auxiliary blower motor resistor assembly with a test light that is connected to ground. Place the front auxiliary blower motor switch in the appropriate speed position for the circuit being tested. Does the test light illuminate on each circuit? If so, go to step  20. If not, go to next step.
  7. Check the applicable circuit between the auxiliary blower motor resistor assembly and the corresponding auxiliary blower motor relay for an open or high resistance. See WIRING DIAGRAMS . Did you find and correct the condition? If so, go to step  33. If not, go to next step.
  8. Turn the ignition off. Disconnect the applicable auxiliary blower motor relay. Turn the ignition on, with the engine off. Connect a test light between the ignition 3 voltage circuit of the auxiliary blower motor relay and ground. Does the test light illuminate? If so, go to next step. If not, go to step  25.
  9. Connect a test light between the battery voltage circuit of the auxiliary blower motor relay and ground. Does the test light illuminate? If so, go to next step. If not, go to step  26.
  10. Connect a test light between the battery voltage circuit and the control circuit of the auxiliary blower motor relay. Place the front auxiliary blower motor switch in the appropriate position for the circuit being tested. Does the test light illuminate? If so, go to step  19. If not, go to next step.
  11. Check the applicable control circuit of the auxiliary blower motor relay between the relay and the front auxiliary HVAC control assembly for an open or high resistance. See WIRING DIAGRAMS . Did you find and correct the condition? If so, go to step  33. If not, go to step  22.
  12. Check the ground circuit of the auxiliary blower motor for a high resistance. Did you find and correct the condition? If so, go to step  33. If not, go to step  21.
  13. Does the auxiliary blower motor operate in any rear auxiliary blower motor switch speed position? If so, go to next step. If not, go to step  15.
  14. Check the applicable blower motor control circuit of the rear auxiliary HVAC control assembly between the rear auxiliary HVAC control assembly and the splice for an open or high resistance. See WIRING DIAGRAMS . Did you find and correct the condition? If so, go to step  33. If not, go to step  23.
  15. Turn the ignition off. Disconnect the front auxiliary HVAC control assembly. Turn the ignition on, with the engine off. Place the rear auxiliary blower motor switch in the maximum speed position. Connect a 3-amp fused jumper wire between the auxiliary blower motor switch control circuit of the front auxiliary HVAC control assembly and ground. Does the auxiliary blower motor operate? If so, go to step  22. If not, go to next step.
  16. Turn the ignition off. Disconnect the auxiliary HVAC control processor. Turn the ignition on, with the engine off. Connect a 3-amp fused jumper wire between the auxiliary blower motor switch control circuit of the auxiliary HVAC control processor and ground. Does the auxiliary blower motor operate? If so, go to next step. If not, go to step  18.
  17. Check the auxiliary blower motor switch control circuit between the front auxiliary HVAC control assembly and the auxiliary HVAC control processor for an open or high resistance. See WIRING DIAGRAMS . Did you find and correct the condition? If so, go to step  33. If not, go to step  24.
  18. Check the auxiliary blower motor switch control circuit between the rear auxiliary HVAC control assembly and the auxiliary HVAC control processor for an open or high resistance. See WIRING DIAGRAMS . Did you find and correct the condition? If so, go to step  33. If not, go to step  23.
  19. Inspect for poor connections at the harness connector of the applicable auxiliary blower motor relay. Did you find and correct the condition? If so, go to step  33. If not, go to step  27.
  20. Inspect for poor connections at the harness connector of the auxiliary blower motor resistor assembly. Did you find and correct the condition? If so, go to step  33. If not, go to step  28.
  21. Inspect for poor connections at the harness connector of the auxiliary blower motor. Did you find and correct the condition? If so, go to step  33. If not, go to step  29.
  22. Inspect for poor connections at the harness connector of the auxiliary blower motor switch, without rear A/C, or the front auxiliary HVAC control assembly, with rear A/C. Did you find and correct the condition? If so, go to step  33. If not, go to step  30.
  23. Inspect for poor connections at the harness connector of the rear auxiliary HVAC control assembly. Did you find and correct the condition? If so, go to step  33. If not, go to step  31.
  24. Inspect for poor connections at the harness connector of the auxiliary HVAC control processor. Did you find and correct the condition? If so, go to step  33. If not, go to step  32.
  25. Repair the ignition 3 voltage circuit between the splice and the relay for an open or high resistance. After repairs are complete, go to step  33.
  26. Repair the battery voltage circuit between the splice and the relay for an open or high resistance. After repairs are complete, go to step  33.
  27. Replace the appropriate auxiliary blower motor relay. See REMOVAL & INSTALLATION . After repairs are complete, go to step  33.
  28. Replace the auxiliary blower motor resistor assembly. See AUXILIARY BLOWER MOTOR RESISTOR  under REMOVAL & INSTALLATION. After repairs are complete, go to step  33.
  29. Replace the auxiliary blower motor. See AUXILIARY BLOWER MOTOR  under REMOVAL & INSTALLATION. After repairs are complete, go to step  33.
  30. Replace the appropriate blower motor switch. See REMOVAL & INSTALLATION . After repairs are complete, go to step  33.
  31. Replace the rear auxiliary HVAC control assembly. See AUXILIARY HVAC CONTROL ASSEMBLY  under REMOVAL & INSTALLATION. After repairs are complete, go to step  33.
  32. Replace the auxiliary HVAC control processor. See AUXILIARY HVAC CONTROL PROCESSOR  under REMOVAL & INSTALLATION. After repairs are complete, go to step  33.
  33. Operate the system in order to verify the repair. Did you correct the condition? If so, system is okay. If not, go to step  2.
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