What Is a Blend Door Actuator & How to Replace?

You were caught off guard when one morning, the heater didn't blow hot air anymore. Or your air conditioning didn't blow cold air on a particularly hot summer day.

The most probable reason is that the blend door actuator must be broken. However, what is a blend door actuator? Also, how to replace it?

These must be your questions as a blend door actuator is often overlooked because of their small appearance.

But, they play a vital role in regulating the temperature inside your car so you can be comfortable while driving.

Functions of a Blend Door Actuator

A blend door actuator is located near the driver or the passenger's side. Most cars have two to four blend door actuators.

One for the driver and the others at the passenger's side. Determining the driver's side blend door actuator is easy. It's located in the foot wheel just behind the lower floor panel near the driver's seat.

On the other hand, the blend door actuator at the passenger's side is just behind the glove box.

Blend door actuators are also called HVAC actuators. HVAC is short for heating, venting, and air conditioning systems used in air temperature regulation.

These control the positioning of the vents or the blend door which control the air flow. In fact, these actuators are small motors powered by electricity but they can also be controlled mechanically.

They control or regulate the inside temperature through mixing hot air with cold air. Normally, a car has a heater core where warm air comes from. If you turn on the heater, the actuator will direct the air coming from the heater core to the vents.

In another scenario, if you turn on the air conditioning, the heater core will still function. But, the air will be directed from the heater core.

Without a blend door actuator, it can cause discomfortbecause you would appear to be a sitting duck being fried inoil.

If it's winter, you may not be spared from the cold temperature while inside your vehicle. Also, driving without a blend door actuator will not retard or cause malfunction to the car's systems and performance.

Types of Blend Door Actuators

As mentioned previously, these actuators can be either mechanical or electronic. A mechanical blend door actuator has a lever at the HVAC panel on the dashboard. This lever is connected to a cable which also connects to the blend door.

Then, the blend door moves when you control the lever through selecting your preferred temperature.

On the other hand, an electronic blend door actuator moves automatically. The motor is controlled by a computer. Just like in an aircon, the computer will automatically move the vents and for how long.

An electric blend door actuator has two parts: the motor and the plastic gear set. The actuator is linked to the vents and a plastic gear set is rotated from left to right by the motor.

Symptoms of a Faulty to Broken Blend Door Actuator

Just like any mechanical device, a blend door actuator will fail eventually in the long run. Fortunately, there are a few tell-tale signs that will tell you if your blend door actuator is not working well.

For example, if the coldness or warmness while inside your car is not the same as you used to, that's a sign. Also, air conditioning may be present on one blend door actuator but not on the other.

Another thing is when you only get one type of air. For instance, you can access the heater but not the air conditioner or vice-versa.

Another signal that there’s something wrong with the blend door actuator is when you hear clicks or ticking noise coming from the dashboard.

Furthermore, you can tell it's downright broken when it blows hot air instead of cold when you definitely selected air conditioning mode.

It becomes broken in at least two ways. One is when the electric motor of the actuator had given up or had burned out. This makes the actuator unresponsive to the operatingcontrols.

Second, the plastic gear set of the actuator has broken which gives off the ticking noise. The next for the ticking noise is silence which only means that it won't function again.

To know which of the actuators are not working properly, simply turn on either the heater or the air conditioning full blast.

One will be functional in delivering the side temperature but the other one will not. For example, the cold air will flow only to the passenger's side but not to the driver's side.

Fixing Blend Door Actuator

A blend door actuator is made of a plastic housing with its motor inside and the plastic gear set. It is positioned withscrews. Some blend door actuators fail earlier than the others. However, these factors depend on the vehicle make and its year of manufacture.

Now, for the main question: is a broken blend door actuator fixable? The answer is no. First and foremost, the motor failed which made the actuator unresponsive.

Fixing the motor is tantamount to replacing the whole blend door actuator. Fortunately, buying a replacement won’t cause you a fortune.

Replacing Broken Blend Door Actuator

We place emphasis on replacing of your actuator if it's not working anymore. Discomfort may be one of the immediate reasons but it's the potential damage to your air conditioning system that we worry about.

You may replace the blend door actuator on your own or with the help of a mechanic. But, labor costs may be more than a hundred of dollars depending on where the blend door actuator is located.

1. With the help of an expert

The technician or mechanic will first diagnose the problem before trying to remove the actuator.

He will first attempt to turn on the HVAC system and will select each vent position. Also, the temperature range is also recorded as the air leaves the vents. Of course, he will also check if the vents function properly.

If it's for certain that the blend door actuator is at fault, the removal of the actuator will be performed. If it’s hidden under the dashboard, he will remove the dashboard.

Then, he will test the motor through bench test before deeming it for replacement. However, if the actuator doesn't respond to testing, it is broken and needs to be replaced.

Labor costs of removing the blend door actuator vary. This is because there could be multiple broken blend door actuators and they're located in different areas.

You could save more when it's located in an accessible location and without the need to dismantle the dashboard. Some car models have their dashboard already assembled before they're put inside the vehicle.

Thus, when one part needs replacement, some cars models require the removal of other parts first.

He will install a new blend door actuator in the original place and close up everything that was dismantled. Finally, the technician will test the heating and cooling system of the vehicle again.

2. Do it yourself

This method is applicable if you don't have the budget for paying a mechanic or technician. You can even save a hundred of dollars because you will do yourself the required labor.

However, this method is only recommended when the broken actuators require simple removal. To give further detail, you should not remove other complex parts like steering wheel, airbags, or even the dashboard on your own.

The tools you will need for DIY is a socket wrench. Actuators are held by three to four bolts. Remove the cover hiding the actuator and proceed to test the vehicle again.

Adjust the temperature of your HVAC and observe if the actuator is responding as it should. If the motor is not turning, turn off the vehicle and proceed to the removal of the blend door actuator.

Turning off the engine of the car makes sure that you won't be electrocuted. Remove the electric connectors connecting to the broken actuator. Next, remove the bolts or fasteners securing the actuator to the HVAC assembly with the socket wrench.

Related: Best Torque Wrench – Reviews & Buyer’s Guide

Then, with a new blend door actuator, secure the electrical connectors back. Hearing a click signals the correct installation of the connector.

Lastly, fasten it in place with the bolts. Be gentle with the process as the actuator is quite fragile because of its plastic construction. Reinstall the cover or the glove box afterward.

Try turning on the engine again and select the desired temperature. If your installation is right, the new blend door actuator should function well.

Don't forget to install a blend door actuator that is the exact replica of the broken one! Blend door actuators vary in appearance depending on the car model, etc.


Understanding the functions of a blend door actuator may be unfamiliar at first. But, through the help of the discussions and guideline above, you now have an idea what a blend door actuator is.

 Remember that if you don’t have the mechanicalbackground or have no idea how to replace broken car parts, it’s best to heed the advice of an expert. But, if you can do it on your own, you can enjoy that fresh, cold blow of air in under an hour of tinkering!

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