What is a Blend Door Actuator (Everything To Know)

The blend door actuator may seem strange because it is not a common part of cars. However, it is an essential component of your car’s air conditioning system.

Therefore, when the blend door actuator fails, your vehicle will have noticeable symptoms.

You can still drive your car with a blend door actuator problem, but it can create discomfort for you inside the car.

In this article, you will learn everything you need to know to about your vehicle’s blend door actuator, what it does, the symptoms of a bad blend door actuator, and how to go about replacing a bad blend door actuator.

However, it can be challenging to locate, especially if you’re not an experienced mechanic or technician.

The function of the blend door actuator is vital. The signal that comes from dialing to increase or decrease the temperature in your car goes through the blend door actuator. The defroster and other vents are also controlled by it.

Some modern cars have two blend door actuators, especially the back seat control temperature and airflow intensity.

What Does a Blend Door Actuator Do?

What Does a Blend Door Actuator Do

The Air blend door actuator comprises a plastic housing, a small electric motor, and a plastic gear set.

A sensor for sending feedback information to the climate control computer is also incorporated into the blend door actuator.

The actuator carries temperature and air direction doors into the heater plenum box designed to control mode settings like temperature flow, mod vent, defrost, and fresh air or recirculation modes.

The actuator also influences the right and left passenger compartment temperature settings.

When the actuator receives an electric command from your car’s climate control computer, it will start changing air direction mode.

The driver or passenger determines the direction of this airbase based on what they choose from the dual climate control systems.

Most car systems have three to four units installed at various locations around the HVAC plenum that are in charge of mode operation and are different based on the car make and model.

Blend Door Actuator Symptoms

The following are bad blend door actuator symptoms

1. Knocking Sounds

Knocking sound is a common symptom of a bad blend door actuator. When you start hearing a knocking sound as you start your AC system, then it’s an indication of a bad or failed blend door actuator, and you need to replace it as soon as possible.

2. Wrong Temperature

When your blend door actuator stops working altogether, you might start getting the wrong temperature.

Depending on how well it is working, it will start to vent cold or hot air, according to the instructions from the control unit.

However, if you are still getting the wrong temperature despite adjusting the temperature for a few minutes, this indicates a malfunctioning blend door actuator.

3. Clicking Noise

When you start hearing a clicking sound from your dashboard, it could be a possible sign of a bad blend actuator.

The intensity of this sound could be faint, but it will be constant. You will notice the sound strongly around the HVAC control on your dashboard.

Get your car inspected by a professional mechanic for a proper fix when this sound surfaces.

4. Inconsistent Airflow

When you start noticing inconsistent airflow from your car vent, it could mean your blend door actuator has become faulty.

This occurs when the blend door starts moving back and forth rapidly or inconsistently, resulting in inconsistent airflow.

5. Any Other Strange Noises

You can also notice other unusual noises within your dashboard, and it could be a possible sign of a bad blend door actuator.

When you start hearing droning or squeaking sounds coming from the center of your dashboard, especially when you take a turn or change the temperature level of your air conditioner, don’t hesitate to call a professional when you start hearing such unusual noises.

6. Inconsistent Temperature

When you notice that the temperature coming out from your car’s vent is changing consistently and repeatedly without you touching or changing it from the control point, then this could mean that your blend door actuator is no longer functioning correctly.

Also Read: Radiator Repair Options And Which You Should Choose

Can I Drive With a Faulty Blend Door Actuator?

Can I Drive With a Faulty Blend Door Actuator

Yes, you can drive your car even if you have a faulty blend door actuator; however, we don’t recommend that you ignore it or let it continue for a long time.

The blend door actuator will not affect your driving because it is just a comfort feature inside the main cabin.

However, if it gets faulty or breaks, you will start noticing strange noises or difficulty setting the desired temperature in your car.

This can be quite uncomfortable and inconvenient for you and your passengers. This is why you should fix the problem as soon as you notice it.

How to Calibrate Blend Door Actuator

Here are the steps to calibrate a blend door actuator

  1. Slot the car key in the ignition, move it towards the on, and turn the HVAC system.
  2. Move the key to the off position.
  3. Open the hood (bonnet for the RHD guys) and search for fuse #15 in the fuse box beside the battery.
  4. Bring out of the fuse and wait 1-2 minutes for any capacitive charges in the system to dispel.
  5. Slot in a new fuse.
  6. Move the key to the on position. You will now notice that the motor moves as the system goes through the calibration routine. Please don’t turn it off until the calibration routine is completed. There will also be other activities as the door and fan are calibrated.

Running the calibration routine a couple of times will help restore the system to full functionality.

Initially, you will notice that the door, which is significantly different from the failure point, will successfully shift towards the new, correct position setting.

However, the system has to undergo several cycles to achieve the new position setting.

Check Out this video for more tips on blend door actuator recalibration

Also Read: Blend Door Actuator Replacement (Cost & Steps)

Frequently Asked Questions About Blend Door Actuator

What Happens if the Blend Door Actuator Is Bad?

When your car blend door actuator gets bad, the blend door will no longer be working, and you will find it difficult to adjust or change the temperature intensity. Sometimes, it could get stuck in just one setting or be venting out inconsistent temperatures.

How Much Does It Cost to Fix a Blend Door Actuator?

The cost of a blend door actuator is between $100 – $300, depending on the car’s make and model, excluding labor costs.

What Causes a Blend Door Actuator to Fail?

The blend door actuator is connected to an air control door pivot located on the last drive of the unit. An electric motor rotates a plastic gear set from one side to another; when the plastic gear set becomes fragile and eventually breaks, the actuator will become faulty and fail.

Can You Drive Without a Blend Door Actuator?

You can drive without a blend door actuator because it has nothing to do with the driving systems. However, a bad blend door actuator can cause discomfort to both you and your passengers since it affects the car’s temperature.

How Long Does It Take To Fix a Blend Door Actuator?

It will take about one to two hours to fix and test a blend door actuator.

Can a Bad Blend Door Actuator Drain Battery?

A bad blend door actuator can run down your car battery when the AC stays on for too long.

Why Is My Car Blowing Hot Air on One Side and Cold Air on the Other?

The most common symptom of a bad blend door actuator is that your car will be blowing cold air on one side and hot on the other. This problem can be diagnosed using an advanced scan tool. The blend door actuator should be replaced when this problem surfaces.

What Does an Hvac Blend Door Actuator Do?

An HVAC blend door actuator is an electric motor that works with sensors linked to the climate control system. The actuator receives and gives out that signal when you initiate the temperature dial.

How Do You Reset the Blend Door Actuator on a Ford?

Bring out the fuse of the actuator from the fuse panel located in the driver’s footwell. This is the first thing you need to do. Let the AC system run for a few minutes when you are done with that. Finally, put off the car and insert back the fuse to see if the blend door is working.

What Is the Difference Between a Mode Door Actuator and a Blend Door Actuator?

Blend door handles the rate at which air blows through the heater core; it also controls the temperature, while the mode door controls the vents and the air that comes through it.

Do You Have to Calibrate a Blend Door Actuator?

After replacing an actuator, calibration is necessary. However, if power is removed, it won’t be required anymore. The air conditioning, temperature, and air distribution blend will self-calibrate when power gets restored.

How Many Blend Door Actuators Does My Car Have?

Most cars have up to two blend door actuators; however, vehicles with the ability to handle temperature at different zones or multiple zone climate control can have more. The actuator operates the activities of the blend door; it can also divert and influence airflows.

What Controls the Blend Door Actuator?

The actuator controls the blend door, which also diverts and influences airflow. Some plastic gears manage them; they move the blend door when the actuator sends the correct signals. The blend door is a flat-panel plastic; that is why it is called a door.

Conclusion

Blend door actuators are unpopular car parts; they are often not discussed because they do not affect the driving system.

However, they can affect your driving experience if they malfunction. You can’t see them until you open your car dashboard, and you barely notice them because they often work perfectly.

As long as there are no manufacturing shortfalls, the blend door actuators will last for a long time.

This means they don’t require regular replacement or maintenance, saving you money and time.

Scott Greene is a seasoned automotive technician for over 5 years and has been deep into advanced automotive diagnostics for a couple of years. He Loves writing about Automotive Diagnostics and Repair, Trouble codes, Buyer guides for various car parts and accessories, and lots more. 

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