3 SYMPTOMS OF A BAD BLEND DOOR ACTUATOR

The purpose of the blend door actuator is to open the blend door based on the position of the temperature control knob. In simple terms, the blend door is what allows hot or cold air to come through the interior of the car. Older cars don't have an actuator, instead, they have a cable that’s connected from the control knob to the blend door. 

location

The location of the blend door actuator will typically be in either one of the locations pointed out with arrows in the picture. If you have dual-zone climate control, you’ll have one on each side.

If you have a larger vehicle like an SUV or a minivan that has rear heating and cooling, it can be behind this panel pointed out with an arrow in the picture.

symptoms

tapping noise

The first symptom of a bad blend door actuator you might be experiencing is hearing a tapping noise either when starting the car or when moving the temperature control. The noise could be heard behind the dashboard, or if you have a rear climate control it can be heard towards the back of the car. This could be caused by broken gear teeth inside the actuator.

temperature stuck on hot

The second symptom of a faulty blend door actuator is the temperature stuck on hot. You’ll be trying to switch from hot to cold but notice there is no difference in the temperature. This could be caused by internal damage that prevents the gears from rotating. In other situations, it could be caused by a failed motor. Both will prevent the blend door from moving, resulting in the temperature remaining on hot.

temperature stuck on cold

On the flip side, the third symptom could be the temperature stuck on cold. Similarly to the previous symptom, this could be caused by internal damage to a blend door actuator or a failed motor.  It all depends on when the actuator failed.

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If you have dual-zone climate control, it's likely that only the passenger or driver side is experiencing these symptoms, because each side has its own blend door actuator. If you have rear climate control, you may also notice these symptoms on the back end of the vehicle due to an extra actuator.

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If you concluded that your blend door actuator needs to be replaced and you want to do it yourself, I would recommend getting a repair manual here. You can use code “AD10VA” for 15% off one-year subscriptions for any US Order.

You can also buy a new blend door actuator here.

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