The air temperature actuator is a 2-wire bi-directional electric motor. There are 2 control circuits that enable the actuator to operate. The control circuits use either a 0 or 12-volt value to coordinate the actuator movement. When the actuator is at rest, both control circuits have a value of 0 volts. In order to move the actuator, the HVAC control module grounds one of the control circuits while providing the other with 12 volts. The HVAC control module reverses the polarity of the control circuits to move the actuator in the opposite direction.

Inspect the air temperature door and the mode actuator for the following conditions:

Schematic Reference

HVAC Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for Scan Tool Information

1. Ignition ON, engine running, place the blower motor switch at the maximum speed position and the mode switch in the vent or panel position.
2. Rotate the air temperature control switch from the full COLD position to the full HOT position. The air temperature should follow the commanded states of full HOT to full COLD through the vent or panel positions.

1. Ignition OFF, disconnect the harness connector at the air temperature actuator.
2. Ignition ON, connect a test lamp between the control circuit terminal A and control circuit terminal B. Command the actuator in each direction. The test lamp should briefly illuminate when commanding the actuator in one direction to the other direction.

⇒	If the test lamp is always OFF, test the appropriate control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the HVAC control module.

⇒	If the test lamp is always ON, test the appropriate control circuit for a short to voltage. If the circuit tests normal, replace the HVAC control module.

3. If all circuits test normal, test or replace the air temperature actuator.

1. Install a 10-amp fused jumper wire between the control terminal A and 12 volts. Momentarily install a jumper wire between the control terminal B and ground. The air temperature actuator shaft should rotate.

⇒	If the function does not perform as specified, replace the air temperature actuator.

2. Reverse the jumper wires; the air temperature actuator shaft should rotate.

⇒	If the function does not perform as specified, replace the air temperature actuator.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.