The blower motor speed control, battery positive and ground circuits enable the control module to operate. The HVAC control module provides a pulse width modulation signal to the blower motor in order to command the blower motor speed.

The blower motor draws more amperage than the HVAC control module is calibrated for.

Schematic Reference

HVAC Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

Scan Tool Reference

Control Module References

Ignition ON, operate the blower fan speed(s).

1. Ignition OFF, disconnect the harness connector at the blower motor.
2. Ignition ON, connect test lamp at the battery positive voltage terminal A and ground.

⇒	If the test lamp does not illuminate, test the battery positive voltage circuit for short to ground or an open/high resistance.

3. Connect test lamp between the battery positive voltage terminal A and the control circuit terminal B. The test lamp should dimly illuminate at high speeds and reduce in intensity as the blower speed is reduced.

⇒	If the test lamp does not illuminate. Test the control circuit for short to voltage or an open/high resistance. If the circuit tests normal, replace the HVAC control module.

⇒	If the test lamp stays illuminated all the time. Test the control circuit for short to ground. If the circuit tests normal, replace the HVAC control module.

⇒	If the test lamp does illuminate and change intensity. Test or replace the blower motor..

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.