GM Service Manual Online
For 1990-2009 cars only

The HVAC system also uses two bi-directional DC mode valve actuators.

The actuators operate on signals from the A/C control. The signals are inputs from the following items:

    • The in-vehicle temperature
    • The outside air temperature
    • The set temperature
    • The input from the solar sensor

While the actuators turn, the actuators move the temperature valves in the HVAC module. The temperature valves then obtain the correct blend of heated air from the heated and cooled air from the A/C evaporator.