Blend Door Motor Replacement

How to Replace a Blend Door Motor

First of all let’s bet an idea of what a blend door motor does. Inside your car; heat comes from the air passing over the heater core and cold air comes from the air passing over the air conditioner evaporator. Inside the heater box is where the blend door is actuated by a blend door motor that closes and opens it depending on the temperature selected inside the vehicle. To find out if your blend door motor is working properly, start engine and select the low fan setting and move the climate control from cold to warm and back while listening to the sound of the blend motor through the vents. 

You should hear it activate while changing from warm to cold. If you only have heat then you may have a vacuum leak or your blend door motor is bad and should be replaced. To give you an idea of what is involved it replacing the blend door motor, you have to see where it is located. If behind the dash sounds like a tough spot to be located and you are right, it is but not impossible. On some vehicles, you can access the blend door motor without removing anything from under the dash, while others require massive disassembly. If you have the latter, here are some tips.

You will be working under the car dash so wear appropriate protective clothing, gloves and eyewear. Park your car on level ground and set the emergency brake.

Tools Needed to Complete this Repair Job

1.Screw Driver

2.Sockets and Wrenches

3. Pliers


Step 1 - Get a diagram of your vehicle’s heater and air conditioner system and the component locations of the blend door motor and actuators.

Step 2 - Remove the dash enough to access the heater box. Leave as much intact as possible, you only need to get enough room to get the heater box out, but don’t force it.

Step 3 - Disconnect the electrical connector from the blend door motor.

Step 4 - Remove the heater box (if needed)

Step 5 - Disconnect the linkage from the blend door motor and the actuator

Step 6 - Remove the blend door motor and replace with new.

Step 7 - Connect linkage to blend door motor, always check that the blend door moves freely before installation

Step 8 - Install heater box

Step 9 - Connect electrical connection to the blend door motor

Best Practices

If further technical assistance is needed, our certified car repair technicians are ready to answer your car questions. For manufacturer specific repair information visit - Car Repair Manuals

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Written by
Co-Founder and CEO of
35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.


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Article first published (Updated 2015-01-05)