Do you hear a ticking noise from your dash when the ignition key is on? Does
your car heater blow cold or the air conditioner blow hot? These are signs that a blend
door actuator has gone bad. With a little help from our team of ASE certified
mechanics and about a half hour of your time you can replace this part to get your climate control back working
again. Or you can see what you are paying for when taking your car in for
What Goes Wrong?
A blend door actuator is made up of an electric motor that turns a plastic
gear set in one direction or another which is connected to an air control door
pivot at the final drive of the unit. An actuator can go bad in of two 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 plastic 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. This is a common problem in most car's heater and air conditioner
How Does It Work?
An air blend door actuator is constructed from a plastic housing, a small
electric motor and a plastic gear set. A door position sensor is also
incorporate into the unit to send feed back information to the climate control computer.
This actuator then moves temperature and air direction doors
inside the heater plenum (box) which are designed to control mode settings such
as temperature, floor, mid vent, defrost and fresh air or re-circulation modes.
They also control hot and cold settings for right and left passenger compartments.
Your car's climate control computer gives an electrical command to the actuator to start
moving the actuator motor to change air direction modes. This direction is according to
the temperature chosen by the driver or passenger on dual climate control
Most systems have three to four of these units placed in various areas around
the HVAC plenum that control mode operation and will vary by the car make and model.
Let's Get Started
You can get an OEM replacement actuator from
Amazon for what the garages pay for them in most cases.
You will need a tool set including
an 5.5 mm socket for Chevy, GMC, Cadillac, Ford and Lincoln vehicles.
Step 1: Remove the Lower Dash Panel or Glove Box
Using a small socket and ratchet remove the mounting bolts that hold the
under dash plastic cover on the passenger side. These screws can be in obscure places so look around for them.
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.
Here is what it looks like when the glove box is removed exposing the blend door
actuator for replacement.
Step 2: Remove the Door Actuator
Here is a typical right side temperature actuator used for dual climate controls (also temperature for signal mode units).
This actuator hangs below the box which is one of the
easier units to replace.
Begin by using a small screwdriver to release the wiring safety
clip on the harness for the actuator. These clips can be brittle and break so be
Once released gently pull down on the wiring connector and remove it from the
blend door actuator. Inspect the connector for rust or corrosion and clean as needed.
Step 3: Remove the Actuator
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.
Once all of the mounting screws have been removed the actuator should become loose.
Grasp the actuator and pull it from its mount to remove.
Step 4: Turn the Air Door Pivot
Before installing the new actuator it's a good idea to manually turn the
blend door in both directions to ensure it is not stuck which will cause the new
actuator to fail. 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 of the door movement 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.
To test the blend door operation and too double check that you are changing the
correct actuator motor turn the blower motor on and work the door in each way.
You will be able to feel the air change temperature or vent level.
Step 5: Match the New Actuator
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 6: Install the New Air Blend Door Actuator
Install the new part in place as you insert the mounting screws by hand.
Be careful not to cross thread the mounting screws because they thread into the plastic
housing and can easily strip, (do not over tighten).
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
Step 7: Reinstall the Cover or Glove Box
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.
Once the cover is in place start the installation of the mounting screws by
hand, once hand threaded 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
After cover has been re-installed start the engine to test the repair job by
turning the climate control on and moving the controls from hot and cold and from defrost to the mid and floor
positions to ensure the new actuator is working as it should.
Watch the Video
Here is this job being done to pick up on additional tips and information before you begin.
Blend Door Actuator Locations
Begin by identifying the problem either defrost, mid or floor, or
temperature modes not working. Then locate and identify the actuator to be replaced.
These units can be either hanging in front of you or in a little more obscure places such as on the side the
HVAC plenum. Sometimes they can be located in inconvenient places
like the top of the heater box. These repairs can take a little longer because
more parts need to be removed to gain access to the actuator.
You can use a repair resource such as Mitchell1, a paper manual
found on Amazon or a resource like Google images to locate the
particular area in which the actuator needs to be replacement.
Here is an example of a Silverado, Suburban and Tahoe locations.
Mode (Defrost Mid Vent and Floor) Actuator Location
Right Temperature Actuator Location - Signal System Temperature Actuator