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Test A: Auxiliary Blower Motor Always On

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: Definition: The auxiliary blower motor is On while the auxiliary blower motor switch in the OFF position.
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: For circuit reference, see CONNECTOR IDENTIFICATION  and/or WIRING DIAGRAMS  .
  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 auxiliary blower motor switch in the OFF position. Is the auxiliary blower motor off? If so, problem is Intermittent. See TROUBLE SHOOTING . If not, go to next step.
  3. Turn the ignition off. Disconnect the auxiliary blower motor switch, auxiliary heat only or the front auxiliary HVAC control assembly, with auxiliary heat and A/C. Turn the ignition on, with the engine off. Does the auxiliary blower motor continue to operate? If so, go to next step. If not, go to step  13.
  4. Probe each auxiliary blower motor control circuit of the auxiliary blower motor switch, auxiliary heat only, or the front auxiliary HVAC control assembly, with auxiliary heat and A/C, with a test light that is connected to battery voltage. Does the test light illuminate when connected to any auxiliary blower motor speed control circuit? If so, go to step  14. If not, go to next step.
  5. Turn the ignition off. Disconnect the auxiliary blower motor resistor assembly. Turn the ignition on, with the engine off. Does the auxiliary blower motor continue to operate? If so, go to next step. If not, go to step  7.
  6. Check the auxiliary blower motor supply voltage circuit for a short to voltage. See WIRING DIAGRAMS . Did you find and correct the condition? If so, go to step  19. If not, go to step  12.
  7. Probe the auxiliary blower motor low speed control circuit of the auxiliary blower motor resistor assembly with a test light that is connected to ground. Does the test light illuminate? If so, go to next step. If not, go to step  9.
  8. Check the auxiliary blower motor low speed control circuit between the auxiliary blower motor resistor assembly and the auxiliary low speed blower motor relay for a short to voltage. Did you find and correct the condition? If so, go to step  19. If not, go to step  10.
  9. Check the auxiliary blower motor medium speed control circuit between the auxiliary blower motor resistor assembly and the auxiliary medium speed blower motor relay for a short to voltage. Did you find and correct the condition? If so, go to step  19. If not, go to step  11.
  10. Inspect the harness connector of the auxiliary low speed blower motor relay for poor connections. Did you find and correct the condition? If so, go to step  19. If not, go to step  15.
  11. Inspect the harness connector of the auxiliary medium speed blower motor relay for poor connections. Did you find and correct the condition? If so, go to step  19. If not, go to step  16.
  12. Inspect the harness connector of the auxiliary high speed blower motor relay for poor connections. Did you find and correct the condition? If so, go to step  19. If not, go to step  17.
  13. Inspect for poor connections at the harness connector of the auxiliary blower motor switch, auxiliary heat only, or front auxiliary HVAC control assembly, with auxiliary heat and A/C. Did you find and correct the condition? If so, go to step  19. If not, go to step  18.
  14. Repair the short to ground in the appropriate auxiliary blower motor speed control circuit of the auxiliary blower motor switch, auxiliary heat only, or the front auxiliary HVAC control assembly with auxiliary heat and A/C. After repairs are complete, go to step  19.
  15. Replace the auxiliary low speed blower motor relay. See AUXILIARY BLOWER RELAYS  under REMOVAL & INSTALLATION. After repairs are complete, go to step  19.
  16. Replace the auxiliary medium speed blower motor relay. See AUXILIARY BLOWER RELAYS  under REMOVAL & INSTALLATION. After repairs are complete, go to step  19.
  17. Replace the auxiliary high speed blower motor relay. See AUXILIARY BLOWER RELAYS  under REMOVAL & INSTALLATION. After repairs are complete, go to step  19.
  18. Replace the appropriate blower motor switch. See REMOVAL & INSTALLATION . After repairs are complete, go to step  19.
  19. 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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