How to Replace a Blend Door Actuator on a Buickby Don Bowman
The blend door actuators in a Buick are electrically operated by blend door motors. A computer assigned to this duty controls the blend door actuators. These are tied into several sensors that detect the outside temperature to compensate for incoming air, inside air temperature and even a sensor to signal when a door or window is open to speed up the fan to maintain the inside temperature.
Open the glove compartment and remove the screws in the door with a Phillips head screwdriver. Remove the rest of the screws around the box itself then remove the box to access the blend door actuators.
Disconnect the electrical connector on the problem actuator. Remove the screws securing the actuator to the HVAC box with the screwdriver. Tip the actuator rearward and disconnect the actuating rod from the blend door actuator arm.
Install the new actuator by inserting the rod into the blend door arm. Swing the actuator in towards the HVAC box, reinstall the screws and tighten. Reconnect the electrical plug to the actuator. Replace the glove compartment box and door and tighten all the screws.