Blend Door Actuator Replacement Guide

Do you hear a ticking noise from the dash when you turn the key on? Does the heater blow cold or the air conditioner blow hot? These are signs that your blend door actuator has gone bad, with a little help from us and about a half hour of your time you can replace this part to get your climate control back working again.

This actuator is used to move temperature and air direction control doors that are designed into the heater plenum box which controls mode settings such as floor, mid vent and defrost and also the temperature of the system such as hot and cold for right and left sides if equipped. An actuator also controls the fresh air or re-circulation modes.

These actuators are made up of an electric motor that turns a plastic gear set one direction or the other which is connected to a air control door pivot at the final drive of the unit.

A climate controller gives an electrical command to the actuator to start moving the motor inside the actuator for full temperature range or air direction modes, and somewhere in-between to mix the air. This direction is according to temperature chosen by the driver or passenger on dual climate controls.

Most systems have three to four of these units placed in various areas around the plenum that control mode operation which will vary by the car make and model. Here is an example of a GM Silverado, Suburban and Tahoe locations.

Recirculation Actuator
Mode (Defrost Mid Vent and Floor) Actuator Location
Right Temperature Actuator Location - Signal System Temperature Actuator
Left Temperature Blend Door Location
You can use a repair manual found on Amazon or a resource like Google images to located your particular area in which the actuator needs to be replacement.

An actuator can go bad in two different ways; first the electric motor can burn out rendering the unit non-responsive so nothing changes when the temperature or vent mode controls are moved. Next, the gear set will become brittle and break which will sometimes allow the unit to work while making a ticking or clicking noise and then stop, or not work and just a noise.

Watch this job being done and enjoy the video, then read down through the article to pick up on additional tips and information before you begin.

Lets Start With The Repair

Before you begin locate and identify the actuator to be replaced. These units can be either hanging right in front of you once the lower plastic dash cover or glove box door is removed, or in a little more obscure spot on one side or the other of the plenum. Sometimes they can be located in inconvenient places like the top of the heater box, for these repairs it can take a little longer to replace. 

You can get an OEM replacement actuator from Amazon for what the garages pay for them, and with prime get them in the same day. You will need a tool set set including a 5.5 mm socket for Chevy, GMC, Cadillac, Ford and Lincoln vehicles.

Step 1

Using a small socket and ratchet remove the mounting bolts that hold the under dash plastic cover in place. These screws can be in obscure places so look around for them.

Step 2

Once you have located and removed all of the mounting screws grasp the cover and gently pull it from the underside of the dash. This will expose the heater box with various controls including any wiring.

Step 3

Here is a right temperature actuator (also temperature for signal mode units) that hangs below the box which is one of the easier units to replace. This particular unit controls the temperature adjustment from hot to cold.  On some vehicles the glove box must be removed to access the actuator while still others will be located above the gas pedal or near the glove box on the passenger side.

Step 4

Begin by using a small screwdriver to release the wiring safety clip on the harness for the actuator.

Step 5

Once released gently pull down on the wiring connector and remove it from the actuator. Inspect the connector for rust or corrosion and clean it as needed.

Step 6

Next, locate and remove the actuator mounting screws, there should be two or three screws holding it in place, a small universal might be needed to help remove the screws in awkward places. Once removed place the screws into a small container so they don't get lost.

Step 7

Once all of the mounting screws have been removed the actuator should become loose, grasp the actuator and pull is straight away from its mount to remove it. After the removal grasp the door pivot and move it back and forth to its full travel, it should move freely. If you cannot move the blend door an obstruction has gotten in the way which will make the new actuator fail.

These obstructions can include: pen, tooth pick, small toy or bubble gum to name a few. If the door is stuck the heater plenum with need to be removed and the problem resolved before installing the new unit.

Step 8

Once removed, compare the bad actuator to the new unit. Be sure to check the wiring harness connector terminals, they should match identically. Now the new part is ready to be installed.

Step 9

Now, hold the new part in place as you insert the mounting screws by hand. Be careful not to cross thread these screws because they thread into the plastic housing and can easily strip, do not over tighten the screws.

Step 10

Once all screws are in place, firmly push the wiring harness connector back into the actuator, you should hear a click signaling the correct installing of the connector. 

Step 11

After the installation is complete, double check your work and reinstall the plastic cover. This can take some jostling to get the bolts holes lined up so hang in there.

Step 12

Once the cover is in place start the installation of the mounting screws by hand, once hand threaded in, install the remainder of the screws. Do not tighten the first screw you have threaded in until all of the screws because it will make the remainder of the screws harder to install.

Step 13

After cover has been re-installed start the engine to test the repair job by turning the climate control on. Move the controls from hot and cold and from the defrost to the mid and floor positions to ensure the new actuator is working as it should.

If you have any questions about the subject you just read about please visit our forum where hundreds of answers have already been given by our mechanics. Learn more


Article first published