Bad Blend Door Actuator Symptoms to be Aware of

A blend door is a part of a motor vehicle’s HVAC system. It plays a part in controlling the airflow and temperature inside the car. Whenever there’s a problem with the A/C system’s temperature, it could be an issue with the actuator of the blend door. Knowing the bad blend door actuator symptoms will help you take quick repair action and save from the damage of other related parts.

What Is a Blend Door Actuator?

The blend door gets its name from its shape. It is a flat plastic panel that looks like a door. It helps with blowing airflow in different directions by being open or closed. This is a simple component but its actuator has a more complicated design.

The actuator is a small plastic box that holds some plastic gears and few other parts inside.

Bad Blend Door Actuator Symptoms

A blend door actuator going wrong means the air conditioning and heating systems won’t function properly. In fact, the HVAC system can malfunction for various reasons. However, if you detect any of the following symptoms, the culprit is definitely the actuator in the blend door.

A Light Clicking Sound

If you’re facing problems with the car’s heating system, pay attention to the dashboard. A faint clicking sound repeatedly coming from underneath the dashboard could mean a bad actuator.

blend door actuator symptoms
A clicking sound from the dashboard is a telling sign. (Source: I, 天然ガス / Wikipedia)

This sound will be the most prominent for a few seconds when you turn on the air conditioning or adjust the temperature. Sometimes, changing the temperature can stop the sound on a temporary basis. However, if you hear the sound whenever using the air conditioning, you can be sure that the problem is with the blend door actuator.

It basically happens because of the deterioration of the plastic gears inside the actuator. The teeth of the gears get damaged over time, and they start slipping off whenever you turn on the A/C.

Knocking Sound

Similarly, a knocking sound could be another indicator of a bad blend door actuator. This is quite uncommon, but whenever you hear this sound, be sure that the actuator is malfunctioning.

The sound is something like a light tapping on the door and it happens when you turn on the A/C system or kick off the car engine.

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Wrong Temperature

Problems with car temperature are strong signs of blend door actuator symptoms. You should check the actuator the car A/C blows too hot air or the airflow that doesn’t heat up to the assigned temperature.

There could be other reasons for the A/C system to function erratically. However, if it’s a faulty actuator, the temperature will either be fixed at a particular point or it will go too high or too low without any input.

Inconsistent Temperatures

It happens when the actuator goes bad in a car that has dual climate control. In that case, the climate control works in one part of the vehicle but doesn’t respond to the other part. Also, the distribution of airflow will be inconsistent if a bad actuator causes the blend door to open and close erratically.