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Test G: Blower Motor Always On - With Auxiliary Heater Only Or Cargo Van With Auxiliary HVAC

WARNING: This page is about a different car, the 2002 GMC Savana Special, 2002 GMC Savana Camper Special, 2002 GMC Savana, and 2002 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: For circuit reference, see CONNECTOR IDENTIFICATION  and/or WIRING DIAGRAMS  .
NOTE: Definition: The auxiliary blower motor is on while the auxiliary blower motor switch in the OFF position.
  1. If review of system operation has been performed, go to next step. If review of system operation has not been performed, see DESCRIPTION  and OPERATION  .
  2. Turn ignition on. Place auxiliary blower switch in OFF position. If auxiliary blower motor is off, problem is intermittent. Check wiring and connectors for damage and poor connections. If auxiliary blower motor is on, go to next step.
  3. Turn ignition off. Disconnect harness connector from auxiliary blower switch (auxiliary heat only), or front auxiliary HVAC control assembly (Cargo Van with auxiliary HVAC). Turn ignition on. If auxiliary blower motor continues to operate, go to next step. If auxiliary blower motor does not operate, go to step  13.
  4. Using a test light connected to positive battery voltage, probe each harness connector terminal of auxiliary blower switch (auxiliary heat only) or the front auxiliary HVAC control assembly (Cargo Van with auxiliary heat and A/C). If test light illuminates on any auxiliary blower motor speed control circuit, go to step  14. If test light does not illuminate on any auxiliary blower motor speed control circuit, go to next step.
  5. Turn ignition off. Disconnect harness connector from auxiliary blower motor resistor. Turn ignition on. If auxiliary blower motor continues to operate, go to next step. If auxiliary blower does not operate, go to step  7.
  6. Check auxiliary blower motor voltage supply circuit (Yellow wire) for a short to voltage. If a short to voltage was found, repair as necessary and go to step  19. If a short to voltage was not found, go to step  12.
  7. Using a test light connected to ground, probe auxiliary blower low speed circuit (Yellow wire) at blower motor resistor connector terminal No. "A". See WIRING DIAGRAMS . If test light illuminates, go to next step. If test light does not illuminate, go to step  9.
  8. Check for a short to voltage in auxiliary blower low speed circuit (Yellow wire) between auxiliary blower motor resistor and auxiliary blower low speed relay. See WIRING DIAGRAMS . If a short to voltage was found, repair as necessary and go to step  19. If a short to voltage was not found, go to step  10.
  9. Check for a short to voltage in auxiliary blower medium speed circuit (Light Blue wire) between auxiliary blower motor resistor and auxiliary blower medium speed relay. See WIRING DIAGRAMS . If a short to voltage was found, repair as necessary and go to step  19. If a short to voltage was not found, go to step  11.
  10. Check harness connector at auxiliary blower motor low speed relay for a poor connection. If a poor connection was found, repair as necessary and go to step  19. If a poor connection was not found, go to step  15.
  11. Check harness connector at auxiliary blower motor medium speed relay for a poor connection. If a poor connection was found, repair as necessary and go to step  19. If a poor connection was not found, go to step  16.
  12. Check harness connector at auxiliary blower motor high speed relay for a poor connection. If a poor connection was found, repair as necessary and go to step  19. If a poor connection was not found, go to step  17.
  13. Check harness connector at auxiliary blower switch (auxiliary heat only), or the front auxiliary HVAC control assembly (Cargo Van with auxiliary HVAC) for a poor connection. If a poor connection was found, repair as necessary and go to step  19. If a poor connection was not found, go to step  18.
  14. Repair short to ground in the appropriate auxiliary blower motor speed control circuit of auxiliary blower switch (auxiliary heat only), or the front auxiliary HVAC control assembly (Cargo Van with auxiliary HVAC). If the repair is complete, go to step  19.
  15. Replace auxiliary blower low speed relay. See Fig 1. After repairs are complete, go to step  19.
    Fig 1: Identifying Auxiliary Blower Motor Relays
    G00067642Courtesy of GENERAL MOTORS CORP.
  16. Replace auxiliary blower medium speed relay. See Fig 1. After repairs are complete, go to step  19.
  17. Replace auxiliary blower high speed relay. See Fig 1. After repairs are complete, go to step  19.
  18. Replace auxiliary blower switch (auxiliary heat only), or the front auxiliary HVAC control assembly (Cargo Van with auxiliary HVAC). If replacement is complete, go to next step.
  19. Operate system to verify repair. If the condition was corrected, system is okay. If the condition was not corrected, return to step  2.
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