Blower Motor Switch: Testing and Inspection

WARNING: ON VEHICLES EQUIPPED WITH AIR-BAGS, REFER TO AIRBAG AND SEAT BELTS/AIR BAGS BEFORE ATTEMPTING ANY STEERING WHEEL, STEERING COLUMN, OR INSTRUMENT PANEL COMPONENT DIAGNOSIS OR SERVICE. FAILURE TO TAKE THE PROPER PRECAUTIONS COULD RESULT IN ACCIDENTAL AIR-BAG DEPLOYMENT AND POSSIBLE PERSONAL INJURY.

1. Turn the ignition switch to the On position and check for battery voltage at the fuse in the fuseblock module. If OK, go to Step 2. If not OK, repair the shorted circuit or component as required and replace the faulty fuse.
2. Turn the ignition switch to the Off position. Disconnect and isolate the battery negative cable. Remove the heater-A/C control from the instrument panel, but do not unplug the wire harness connectors. Connect the battery negative cable. Turn the ignition switch to the On position. Check for battery voltage at the fused ignition switch output (run) circuit cavity of the heater-A/C mode control switch wire harness connector. If OK, go to Step 3. If not OK, repair the open circuit to the fuseblock module as required.
3. Select any one of the heater-A/C mode control positions except Off to turn tile system on. Check for battery voltage at the low blower motor driver circuit cavity of the heater-A/C mode control switch wire harness connector. If OK, go to Step 4. If not OK, replace the faulty heater-A/C mode control switch.
4. Check for battery voltage at the low blower motor driver circuit cavity of the blower motor switch wire harness connector. If OK, go to Step 5. If not OK, repair the open circuit to the heater-A/C mode control switch wire harness connector as required.
5. Check for battery voltage at each of the remaining blower motor switch wire harness connector cavities as you move the switch to each blower motor speed position. Voltage should be present in each cavity at only one switch position. If OK, see the diagnosis for the blower motor resistor and/or the blower motor relay. If not OK, replace the faulty blower motor switch.