LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 41 (HVAC Systems - Manual) >> Symptom Tests >> Test C: Blower Motor Always On

Test C: Blower Motor Always On

WARNING: This page is about a different car, the 2002 Chevrolet Malibu. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: For correct circuit identification and connector terminal locations, 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. Perform DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. Go to next step.
  2. Turn ignition on. Turn blower motor switch to OFF position. If blower motor is operating, go to next step. If blower motor is not operating, problem is intermittent. Check for faulty connections or damaged wires. Repair or replace as necessary. After repair, retest system operation.
  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. Probe blower motor relay high blower motor control circuit with a test light connected to ground. If test light illuminates, go to next step. If test light does not illuminate, go to step  6.
  5. Test high blower motor control circuit for a short to voltage. Repair as necessary, then go to step  14. If circuit is okay, go to step  10.
  6. Probe blower motor supply voltage circuit, from blower motor resistor, with a test light connected to ground. If test light illuminates, go to next step. If test light does not illuminate, go to step  10.
  7. Test blower motor supply voltage circuit between blower motor relay and blower motor resistor for a short to voltage. Repair as necessary, then go to step  14. If circuit is okay, go to next step.
  8. Test low, medium "1", medium "2", and medium "3" blower motor control circuits for a short to voltage. Repair as necessary, then go to step  14. If circuit is okay, go to step  10.
  9. Check for poor connections or connector damage at blower motor relay. Repair or replace as necessary. After repairs are complete, go to step  14. If connections are okay, go to step  12.
  10. Check for poor connections or connector damage at A/C-heater control panel. Repair or replace as necessary. After repairs are complete, go to step  14. If connections are okay, go to step  13.
  11. Repair short to voltage in supply voltage circuit between blower motor relay and blower motor. After repairs are complete, go to step  14.
  12. Replace blower motor relay. See BLOWER MOTOR RELAY  under REMOVAL & INSTALLATION. After repairs are complete, go to step  14.
  13. Replace HVAC control assembly. See HVAC CONTROL ASSEMBLY  under REMOVAL & INSTALLATION. After repair, go to next step.
  14. Operate A/C-heater blower system to verify repair. If blower motor operates normally, repair is complete. If blower motor still malfunctions, go to step  2.
scientia non olet · About LEMON Manuals