GM Service Manual Online
For 1990-2009 cars only

The automatic climate control system (C68) uses the following five actuators in order to adjust the temperature and the air distribution:

    • The electric actuator or the temperature actuator controls the temperature valve.
    • The air inlet actuator controls the air inlet valve.
    • The slave actuator controls the heater slave valve.
    • The mode actuator controls the mode valve.
    • The defroster actuator controls the defroster valve.

When servicing an actuator, replace parts with the correct service parts for the actuator being serviced. The electric actuator for the automatic climate control system (C68) has a green R on the top in order to differentiate the electric actuator from the electric actuator used on the manual climate control systems (C42, C60).

The electric actuator contains a feedback potentiometer. The feedback potentiometer reports the position of the electric actuator to the electronic climate control (ECC) module (Control Assembly). Do not test the electric actuator for movement while disconnected from the heater/vent module with the temperature knob on the control assembly. If the electric actuator is removed or replaced for service the actuator must be initialized. Refer to Temperature Actuator Replacement in Heating, Ventilation and Air Conditioning for the initialization procedure.

The air inlet actuator and the slave actuator are vacuum motors with one vacuum port in order to move the attached valves in one direction.

The mode actuator and the defroster actuator are vacuum motors with two vacuum ports in order to move the attached valves in two directions.