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Test J: Improper Air Delivery (Auxiliary)

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: 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: Air does not flow correctly from the auxiliary air distribution outlets.
  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 rear auxiliary blower motor switch in the maximum speed position. Place the front auxiliary blower motor switch in the OFF position. Is the auxiliary blower motor Off? If so, go to next step. If not, go to TEST A: AUXILIARY BLOWER MOTOR ALWAYS ON .
  3. Place the front auxiliary blower motor switch in the rear control position. Place the rear auxiliary blower motor switch in the Off position. Is the auxiliary blower motor Off? If so, go to next step. If not, go to TEST A: AUXILIARY BLOWER MOTOR ALWAYS ON .
  4. Turn the park lamps On. Place the instrument panel dimmer switch in the brightest position. Place the front auxiliary blower motor switch in each speed position. Does the auxiliary blower motor operate in any speed position? If so, go to next step. If not, go to TEST B: AUXILIARY BLOWER MOTOR INOPERATIVE .
  5. Does the auxiliary blower motor operate in each speed position? If so, go to next step. If not, go to TEST C: AUXILIARY BLOWER MOTOR MALFUNCTION .
  6. 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, go to next step. If not, go to TEST C: AUXILIARY BLOWER MOTOR MALFUNCTION .
  7. Place the front auxiliary blower motor switch in the maximum speed position. Gradually change the front auxiliary mode switch from the vent position to the floor position. Does the air flow from the proper air distribution outlets? If so, go to next step. If not, go to step  9.
    8. NOTE: The park lamps must remain On, with the instrument panel dimmer switch in the brightest position during this step.
  8. Place the front auxiliary blower motor switch in the rear control position. Place the rear auxiliary blower motor switch in the maximum speed position. Gradually change the rear auxiliary mode switch from the vent position to the floor position. Does the air flow from the proper air distribution outlets? If so, condition is intermittent. See SYMPTOM DIAGNOSIS  under TROUBLE SHOOTING. If not, go to step  19.
  9. Place the front auxiliary blower motor switch in the rear control position. Place the rear auxiliary blower motor switch in the maximum speed position. Gradually change the rear auxiliary mode switch from the vent position to the floor position. Does the air flow from the proper air distribution outlets? If so, go to step  16. If not, go to next step.
  10. Turn the ignition off. Disconnect the auxiliary mode actuator. Turn the ignition on, with the engine off. Probe the ignition 3 voltage circuit of the auxiliary mode actuator 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  28.
  11. Check the ground circuit of the auxiliary mode actuator 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.
  12. Measure the voltage from the auxiliary mode door control circuit of the auxiliary mode actuator and ground. Gradually change the rear auxiliary mode switch from the vent position to the floor position. Does the measured voltage continuously increase between zero volts to battery voltage? If so, go to step  23. If not, go to next step.
  13. Check the auxiliary mode door control circuit between the auxiliary mode actuator and the auxiliary HVAC control processor for an open, high resistance, short to ground, or short to voltage. Did you find and correct the condition? If so, go to step  33. If not, go to next step.
  14. Check the ignition 3 voltage circuit of the auxiliary HVAC control processor for an open or high resistance. Did you find and correct the condition? If so, go to step  33. If not, go to next step.
  15. Check the ground circuit of the auxiliary HVAC control processor for an open or high resistance. Did you find and correct the condition? If so, go to step  33. If not, go to step  27.
  16. Turn the ignition off. Disconnect the auxiliary HVAC control processor. Turn the ignition on, with the engine off. Place the front auxiliary blower motor switch in the minimum speed position. At the auxiliary HVAC control processor connector, measure the voltage from the auxiliary mode door control circuit of the front auxiliary HVAC control assembly to ground. Gradually change the front auxiliary mode switch from the vent position to the floor position. Does the measured voltage continuously increase between zero volts and battery voltage? If so, go to step  27. If not, go to next step.
  17. Check the auxiliary mode door control circuit between the front auxiliary HVAC control assembly and the auxiliary HVAC control processor for an open, high resistance, short to ground, or short to voltage. Did you find and correct the condition? If so, go to step  33. If not, go to next step.
  18. Check the ignition 3 voltage circuit of the front auxiliary HVAC control assembly for an open or high resistance. Did you find and correct the condition? If so, go to step  33. If not, go to step  25.
    19. NOTE: The park lamps must remain On, with the instrument panel dimmer switch in the brightest position during this step.
  19. Turn the ignition OFF. Disconnect the auxiliary HVAC control processor. Turn the ignition on, with the engine off. At the auxiliary HVAC control processor connector, measure the voltage from the auxiliary mode door control circuit of the rear auxiliary HVAC control assembly to ground. Gradually change the rear auxiliary mode switch from the vent position to the floor position. Does the measured voltage continuously increase between zero volts and battery voltage? If so, go to step  27. If not, go to next step.
  20. Check the auxiliary mode door control circuit between the rear auxiliary HVAC control assembly and the auxiliary HVAC control processor for an open, high resistance, short to ground, or short to voltage. Did you find and correct the condition? If so, go to step  33. If not, go to next step.
  21. Check the ignition 3 voltage circuit of the rear auxiliary HVAC control assembly for an open or high resistance. Did you find and correct the condition? If so, go to step  33. If not, go to next step.
  22. Check the ground circuit of the rear auxiliary HVAC control assembly for an open or high resistance. Did you find and correct the condition? If so, go to step  33. If not, go to step  26.
  23. Inspect the auxiliary mode door and auxiliary mode actuator for the following:
    • An Incorrectly Installed Actuator
    • Broken Or Binding Linkages
    • Obstruction That Prevents The Auxiliary Mode Door From Operating Within Its Full Range Of Motion
    Did you find and correct the condition? If so, go to step  33. If not, go to next step.
  24. Inspect for poor connections at the harness connector of the auxiliary mode actuator. Did you find and correct the condition? If so, go to step  33. If not, go to step  29.
  25. Inspect the front auxiliary HVAC control assembly for poor connections. Did you find and correct the condition? If so, go to step  33. If not, go to step  30.
  26. Inspect the rear auxiliary HVAC control assembly for poor connections. Did you find and correct the condition? If so, go to step  33. If not, go to step  31.
  27. Inspect the auxiliary HVAC control processor for poor connections. Did you find and correct the condition? If so, go to step  33. If not, go to step  32.
  28. Repair the ignition 3 voltage circuit for an open or a high resistance. After repairs are complete, go to step  33.
  29. Replace the auxiliary mode actuator. See AUXILIARY MODE ACTUATOR  under REMOVAL & INSTALLATION. After repairs are complete, go to step  33.
  30. Replace the front auxiliary HVAC control assembly. See AUXILIARY HVAC CONTROL ASSEMBLY  under REMOVAL & INSTALLATION. After repairs are complete, go to step  33.
  31. Replace the rear auxiliary HVAC control assembly. See AUXILIARY HVAC CONTROL ASSEMBLY (REAR) . After repairs are complete, go to step  33.
  32. Replace the auxiliary HVAC control processor. See AUXILIARY HVAC CONTROL PROCESSOR . 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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