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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 194 (Heater Systems) >> Symptom Tests >> Test B: Auxiliary Blower Motor Inoperative

Test B: Auxiliary Blower Motor Inoperative

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: The auxiliary blower motor is inoperative in 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 headlamp switch in the Off position. Place the front auxiliary blower motor switch in each speed position. Is the auxiliary blower motor inoperative in all speed positions? If so, go to step  4. If not, go to next step.
  3. Turn the headlamps On. Place the instrument panel dimmer switch in the brightest position. Place the front auxiliary blower motor switch in each speed position. Is the auxiliary blower motor inoperative in all speed positions? If so, go to step  9. If not, go to TEST C: AUXILIARY BLOWER MOTOR MALFUNCTION .
  4. 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 the maximum speed position. Does the test light illuminate? If so, go to next step. If not, go to step  6.
  5. Connect a test light between the auxiliary blower motor supply voltage circuit and the auxiliary blower motor ground circuit. Place the front auxiliary blower motor switch in the maximum speed position. Does the test light illuminate? If so, go to step  11. If not, go to step  13.
  6. Check the auxiliary blower motor supply voltage circuit for an open, high resistance or short to ground. Did you find and correct the condition? If so, go to step  16. If not, go to next step.
  7. Check the ignition 3 voltage circuit for an open, high resistance or short to ground. Did you find and correct the condition? If so, go to step  16. If not, go to next step.
  8. Check the battery voltage circuit to the auxiliary blower motor relays for an open, high resistance or short to ground. Did you find and correct the condition? If so, go to step  16. If not, go to next step.
  9. Check the applicable blower motor speed control circuit for a short to ground. Did you find and correct the condition? If so, go to step  16. If not, go to next step.
  10. Check the ground circuit of the auxiliary blower motor switch, auxiliary heat only, or front auxiliary HVAC control assembly, auxiliary heat and A/C, for an open or high resistance. Did you find and correct the condition? If so, go to step  16. If not, go to step  12.
  11. 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  16. If not, go to step  14.
  12. Inspect for poor connections at the harness connector of the auxiliary blower motor switch, auxiliary heat only, or front auxiliary HVAC control assembly, auxiliary heat and A/C. Did you find and correct the condition? If so, go to step  16. If not, go to step  15.
  13. Repair the ground circuit of auxiliary blower motor for an open. After repairs are complete, go to step  16.
  14. Replace the auxiliary blower motor. After repairs are complete, go to step  16.
  15. Replace the appropriate blower motor switch. See REMOVAL & INSTALLATION . After repairs are complete, go to step  16.
  16. 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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