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Test "B": 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 perform the HVAC diagnostic system check? If so, go to next step. If not, see DIAGNOSTIC SYSTEM CHECK  under TROUBLE SHOOTING.
  2. Turn the ignition on, with the engine off. Place the mode switch in the Off position. Is the blower motor off? If so, condition is intermittent. See SYMPTOM DIAGNOSIS  under TROUBLE SHOOTING.
  3. Turn the ignition off. Disconnect the blower motor relay. Turn On the ignition, with the engine off. Does the blower motor continue to operate? If so, go to step  11. If not, go to next step.
    4. NOTE: The mode switch must remain in the OFF position during this step.
  4. Place the blower motor switch in the minimum speed position. Probe the blower motor relay connector terminal No. 87A (Dark Blue wire) with a test light connected to ground. Does the test light illuminate? If so, go to next step. If not, go to step  6.
  5. Test the high blower motor control circuit for a short to voltage. See WIRING DIAGRAMS . Did you find and correct the condition? If so, go to step  14. If not, go to step  10.
  6. Probe the blower motor supply voltage circuit between the blower motor relay and the blower motor resistor with a test light that is connected to a good ground. Does the test light illuminate? If so, go to next step. If not, go to step  9.
  7. Test the blower motor supply voltage circuit between the blower motor relay (Purple wire) and the blower motor resistor for a short to voltage. See WIRING DIAGRAMS . Did you find and correct the condition? If so, go to step  14. If not, go to next step.
  8. Test the low, medium (1), and medium (2) blower motor control circuits for a short to voltage. See WIRING DIAGRAMS . Did you find and correct the condition? If so, go to step  14. If not, go to step  10.
  9. Inspect the blower motor relay for poor connections. See WIRING DIAGRAMS . Did you find and correct the condition? If so, go to step  14. If not, go to step  12.
  10. Inspect the HVAC control assembly for poor connections. Did you find and correct the condition? If so, go to step  14. If not, go to step  13.
  11. Repair the short to voltage on the blower motor supply voltage circuit. See WIRING DIAGRAMS . After repairs, go to step  14.
  12. Replace the blower motor relay. See BLOWER MOTOR RELAY  under REMOVAL & INSTALLATION. After repairs, go to step  14.
  13. Replace the HVAC control assembly. See HVAC CONTROL ASSEMBLY  under REMOVAL & INSTALLATION. After repairs, go to step  14.
  14. 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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