The air temperature actuator is a 5-wire bi-directional electric motor that incorporates a feedback potentiometer. Low reference, 5-volt reference, position signal, and 2 control circuits enable the actuators 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. As the actuator shaft rotates, the potentiometers adjustable contact changes the door position signal between 0-5 volts.

Inspect the air temperature door and the air temperature 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 OFF, disconnect the harness connector at the air temperature actuator.
2. Ignition OFF, test for less than 1.0 ohm between the low reference circuit terminal 1 and ground.

⇒	If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the HVAC control module.

3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 2 and ground.

⇒	If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the HVAC control module.

⇒	If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the HVAC control module.

4. Ignition ON, test for 4.8-5.2 volts between the door position signal circuit terminal 4 and ground.

⇒	If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the HVAC control assembly.

⇒	If less than specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the HVAC control assembly.

5. Connect a test lamp between control circuit terminal 5 and control circuit terminal 3.
6. Command the actuator in both directions with a by using the air temperature control switch from hot to cold. The test lamp should turn ON and OFF with each command.

⇒	If the test lamp is always ON or always OFF during either of the commands, test both control circuits for a short to voltage, short to ground, or an open/high resistance. If the circuits test normal, replace the HVAC control module.

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

1. Install a 10-amp fused jumper wire between the control terminal 5 and 12 volts. Momentarily install a jumper wire between the control terminal 3 and ground. The mode actuator shaft should rotate.

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

2. Install a 10-amp fused jumper wire between the control terminal 3 and 12 volts. Momentarily install a jumper wire between the control terminal 5 and ground. The mode actuator shaft should rotate.

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

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.