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Test H: Blower Motor Always On - Passenger 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 switches is 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 maximum speed position. Place front auxiliary blower switch in OFF position. If auxiliary blower motor is off, go to next step. If auxiliary blower motor is on, go to step  5.
  3. Place front auxiliary blower switch in the REAR CNTL position. Place rear 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 step  20.
  4. Turn ignition off. Place the rear auxiliary blower motor switch in any speed position. Does the rear auxiliary blower motor operate? If so, go to step  25. If not, go to next step.
  5. Turn ignition off. Disconnect front auxiliary HVAC control assembly. Turn ignition on. If auxiliary blower motor continues to operate, go to next step. If blower motor does not operate, go to step  19.
  6. Place rear auxiliary blower switch in OFF position. If auxiliary blower motor continues to operate, go to next step. If auxiliary blower motor does not operate, go to step  14.
  7. Turn ignition off. Disconnect rear auxiliary HVAC control assembly. Turn ignition on. If auxiliary blower motor continues to operate, go to next step. If auxiliary blower motor does not operate, go to step  20.
  8. Using a test light connected to positive battery voltage, probe each blower speed control circuit at rear auxiliary HVAC control harness connector. See WIRING DIAGRAMS . If test light illuminates on any auxiliary blower motor speed circuit, go to step  22. If test light does not illuminate on any auxiliary blower motor speed circuit, go to next step.
  9. 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 blower motor does not operate, go to step  11.
  10. Check voltage supply circuit (Yellow wire) to auxiliary blower motor for a short to voltage. See WIRING DIAGRAMS . If a short to voltage was found, repair as necessary and go to step  29. If a short to voltage was not found, go to step  18.
  11. Using a test light connected to ground, probe auxiliary blower low speed circuit (Yellow wire) at terminal "A" of auxiliary blower motor resistor harness connector. See WIRING DIAGRAMS . If test light illuminates, go to next step. If test light does not illuminate, go to step  13.
  12. Check auxiliary blower low speed circuit (Yellow wire) between resistor and low speed blower motor relay for a short to voltage. See WIRING DIAGRAMS . If a short to voltage was found, repair as necessary and go to step  29. If a short to ground was not found, go to step  16.
  13. Check auxiliary blower medium speed circuit (Light Blue wire) between resistor and medium speed blower motor relay for a short to voltage. See WIRING DIAGRAMS . If a short to voltage was found, repair as necessary and go to step  29. If a short to ground was not found, go to step  17.
  14. Check for a short to ground in auxiliary blower switch control circuit (Dark Blue wire) between rear auxiliary HVAC control assembly and auxiliary HVAC control processor. See WIRING DIAGRAMS . If a short to ground was found, repair as necessary and go to step  29. If a short to ground was not found, go to next step.
  15. Check for a short to ground in auxiliary blower switch control circuit (Light Blue wire) between front auxiliary HVAC control assembly and auxiliary HVAC control processor. See WIRING DIAGRAMS . If a short to ground was found, repair as necessary and go to step  29. If a short to ground was not found, go to step  21.
  16. Check harness connector at auxiliary blower low speed relay for a poor connection. If a poor connection was found, repair as necessary and go to step  29. If a poor connection was not found, go to step  23.
  17. Check harness connector at auxiliary blower medium speed relay for a poor connection. If a poor connection was found, repair as necessary and go to step  29. If a poor connection was not found, go to step  24.
  18. Check harness connector at auxiliary blower high speed relay for a poor connection. If a poor connection was found, repair as necessary and go to step  29. If a poor connection was not found, go to step  25.
  19. Check harness connector at front auxiliary HVAC control assembly for a poor connection. If a poor connection was found, repair as necessary and go to step  29. If a poor connection was not found, go to step  26.
  20. Check harness connector at rear auxiliary HVAC control assembly for a poor connection. If a poor connection was found, repair as necessary and go to step  29. If a poor connection was not found, go to step  27.
  21. Check harness connector at auxiliary HVAC control processor for a poor connection. If a poor connection was found, repair as necessary and go to step  29. If a poor connection was not found, go to step  28.
  22. Repair the short to ground in the appropriate blower motor control circuit of rear auxiliary HVAC control assembly. See WIRING DIAGRAMS . If the repair is complete, go to step  29.
  23. Replace auxiliary blower motor low speed relay. See Figure. After repairs are complete, go to step  29.
  24. Replace auxiliary blower motor medium speed relay. See Figure. After repairs are complete, go to step  29.
  25. Replace auxiliary blower motor high speed relay. See Figure. After repairs are complete, go to step  29.
  26. Replace front auxiliary HVAC control assembly. See FRONT AUXILIARY HVAC CONTROL ASSEMBLY  under REMOVAL & INSTALLATION. After repairs are complete, go to step  29.
  27. Replace rear auxiliary HVAC control assembly. See REAR AUXILIARY HVAC CONTROL ASSEMBLY  under REMOVAL & INSTALLATION. After repairs are complete, go to step  29.
  28. Replace auxiliary HVAC control processor. See AUXILIARY HVAC CONTROL PROCESSOR  under REMOVAL & INSTALLATION. If replacement is complete, go to next step.
  29. 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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