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Test E: 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 blower motor is inoperative in all speed positions.
NOTE: The mode switch must NOT be placed in the OFF position at any time during this diagnostic procedure.
  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 mode switch to any position except Off. Place the blower motor switch in each speed position. Is the blower motor inoperative in all speed positions? If so, go to next step. If not, go to TEST F: BLOWER MOTOR MALFUNCTION .
    3. NOTE: Do not connect the test light to the ground circuit in the blower motor connector.
  3. Turn the ignition off. Disconnect the blower motor. Turn the ignition on, with the engine off. Connect a test light between the blower motor supply voltage circuit and ground. Place the blower motor switch in the minimum speed position. Does the test light illuminate? If so, go to next step. If not, go to step  5.
  4. Connect a test light between the blower motor supply voltage circuit and the blower motor ground circuit. Place the blower motor switch in the minimum speed position. Does the test light illuminate? If so, go to step  11. If not, go to step  9.
  5. Turn the ignition off. Disconnect the blower motor resistor assembly connector. Turn the ignition on, with the engine off. Place the blower motor switch in the minimum speed position. Probe the low blower motor control circuit with a test light that is connected to ground. Does the test light illuminate? If so, go to step  10. If not, go to next step.
  6. Test all blower motor control circuits for a short to ground. Did you find and correct the condition? If so, go to step  18. If not, go to next step.
  7. Turn the ignition off. Disconnect the HVAC control assembly. Turn the ignition on, with the engine off. Probe the ignition 3 voltage circuit of the HVAC control 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  14.
  8. Check the blower motor switch supply voltage circuit for an open, a high resistance or a short to ground. Did you find and correct the condition? If so, go to step  18. If not, go to step  12.
  9. Check the ground circuit of the blower motor resistor assembly for an open or high resistance. Did you find and correct the condition? If so, go to step  18. If not, go to next step.
  10. Inspect for poor connections at the harness connectors of the blower motor resistor assembly. Did you find and correct the condition? If so, go to step  18. If not, go to step  15.
  11. Inspect for poor connections at the harness connector of the blower motor. Did you find and correct the condition? If so, go to step  18. If not, go to step  16.
  12. Inspect for poor connections at the harness connectors of the HVAC control assembly. Did you find and correct the condition? If so, go to step  18. If not, go to step  17.
  13. Check the A/C request signal circuit for a short to ground. Did you find and correct the condition? If so, go to step  18. If not, go to next step.
  14. Repair the ignition 3 voltage circuit of the HVAC control assembly for an open or short to ground. After repairs are complete, go to step  18.
  15. Replace blower motor resistor assembly. See BLOWER MOTOR RESISTOR  under REMOVAL & INSTALLATION. After repairs are complete, go to step  18.
  16. Replace blower motor. See BLOWER MOTOR  under REMOVAL & INSTALLATION. After repairs are complete, go to step  18.
  17. Replace HVAC control assembly. See HVAC CONTROL ASSEMBLY  under REMOVAL & INSTALLATION. After repairs are complete, go to next step.
  18. 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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