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Test E: Blower Motor Always On

NOTE: For circuit reference, see CONNECTOR IDENTIFICATION  and/or WIRING DIAGRAMS  .
NOTE: Definition: The blower motor is ON while the blower motor switch is in the OFF position.
  1. Did you review the DESCRIPTION & OPERATION  and perform SYMPTOM DIAGNOSIS? If so, go to next step. If not, see SYMPTOM DIAGNOSIS  under TROUBLE SHOOTING.
  2. Turn ignition on. Place mode switch in OFF position. If blower motor is off, problem is intermittent. Check wiring and connections. See SYMPTOM DIAGNOSIS  in TROUBLE SHOOTING. If blower motor is on, go to next step.
  3. Turn ignition off. Disconnect blower motor relay. Turn ignition on. If blower motor continues to operate, go to step  11. If blower motor does not continue to operate, go to next step.
    4. NOTE: Mode switch must remain in OFF position during this step.
  4. Place blower motor switch in minimum speed position. Using a test light connected to ground, probe high blower motor control circuit at the blower motor relay. If test light illuminates, go to next step. If test light does not illuminate, go to step  6.
  5. Check for a short to voltage in blower motor control circuit. Repair as necessary, then go to step  14. If circuit is okay, go to step  10.
  6. Using a test light connected to ground, probe blower motor supply voltage circuit between the blower motor relay and the blower motor resistor. If test light illuminates, go to next step. If test light does not illuminate, go to step  9.
  7. Check for a short to voltage in blower motor supply voltage circuit between the blower motor relay and the blower motor resistor. Repair as necessary, then go to step  14. If circuit is okay, go to next step.
  8. Check for a short to voltage in low, medium (1), and medium (2) blower motor control circuits. Repair circuit(s) as necessary, then go to step  14. If circuits are okay, go to step  10.
  9. Check blower motor relay harness connector for loose wires and/or poor connections. Repair as necessary, then go to step  14. If wiring and connections are okay, go to step  12.
  10. Check HVAC control assembly harness connector for loose wires and/or poor connections. Repair as necessary, then go to step  14. If wiring and connections are okay, go to step  13.
  11. Repair blower motor supply voltage circuit between the blower motor relay and the blower motor. After repairs are complete, go to step  14.
  12. Replace blower motor relay. See BLOWER MOTOR RELAY  under REMOVAL & INSTALLATION. After replacement, go to step  14.
  13. Replace HVAC control assembly. See HVAC CONTROL ASSEMBLY  under REMOVAL & INSTALLATION. After replacement, go to next step.
  14. Operate system to verify repair. If system does not operate properly, go to step  2. If system operates correctly, test is complete.
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