The blend door actuator is a component of your vehicle’s HVAC system whose job is to control the temperature and airflow inside.
Whenever you have trouble controlling the air circulating inside your vehicle, or if it’s stuck blowing full blast, or worst of all, when you hear it making a tapping noise as if some kid is outside tapping on your door, you are probably having a problem with your blend door actuator.
Familiarizing yourself with blend door actuator symptoms will save you on costly repairs and allow you perform a quick blend door actuator repair yourself.
What is the blend door actuator?
A mix door actuator is a gauge HVAC electric motor that works together in unison with sensors for your local heating and cooling system.
You adjust the door actuator airflow intensity with the temperature up and down prep dial; the signal is passed on to the actuator.
What does an actuator do? The air will come through the mid-vent, floor vents, control defrost, and so on for a blend door actuator.
Some cars come with a double-blend door actuator, which lets a driver control climate in 2 time zones, as well. You expect to find this dual-blend door actuator standard in most versions of new cars or trucks that have a compatible feature for setting the front or rear passenger climate separate from that for the driver.
The box in question is a plastic box called the blend door, located on the under-trim panel, sending cool or warm air within the passenger compartment of your car for your comfort.
You may need warm air when the vehicle is cold, or vice versa. Turn the climate control dial, and an actuator helps position the blend door so as to send in the air you need. The actuator will close again to prevent heat if you next require cool air.
Blend door actuator symptoms
When any system component of your vehicle goes bad, there will be symptoms that pop up, warning the driver of an issue that needs addressing, and the blend door actuator is no different.
If you’re looking for Tacoma blend door actuator symptoms or any vehicle for that matter, you will find the answers in the paragraphs.
#1. Clicking sound under the dashboard.
If you are having issues with your car’s climate control, then turn on the AC and climate control system and keep a close ear to your dashboard.
If you hear a faint clicking or droning sound repeatedly from the dashboard, in the center area, right where your HVAC control knobs are located, that is an indication of a bad blend door actuator. A quiet clicking or droning sound underneath your dash is usually a blend door actuator noise.
In most cases, this noise will be apparent when you switch on your vehicle’s AC system or turn the climate control dial. In many cases, just the switching of the climate control dial stops the noise temporarily.
You will hear this noise due to a bad door blender in some cases. If the actuator’s plastic gears deteriorate, the teeth will break off and cause it to slip when you turn your HVAC knobs.
#2. Knocking sound under the dash.
This is rare, but whenever you hear a knocking sound beneath the glove box, you are likely dealing with a bad blend door actuator.
Whenever you hear knocking or tapping noises on startup or when you switch on your HVAC, it’s an indication that your blend door actuator has a problem.
#3. Inconsistent temperature.
An Oscillatory period of your blend door might cause the air to flow through somewhere it’s not supposed to. And that’s a good sign your blend door actuator is going bad.
#4. Wrong Temperature.
Malfunctioning climate controls are usually a tip-off that you’ve got a failing blend door actuator. If the air you’re blowing through your vents isn’t making it up to the proper operating temperature or pulls hot where it should be warm, call your mechanic and get that blend door actuator inspected and replaced.
If the plastic gears aren’t slipping, the motor itself has seized. Either way, you won’t be controlling the climate of your car anytime soon.
How do I test the blend door actuator?
If you notice any of the above, inconsistent temperature, knocking sound under the dashboard, clicking sound under the dashboard, or the wrong temperature, you have to test or contact your mechanic for a blend door actuator reset.
Most blend door actuators divert the temperature and airflow in the vehicle by closing and opening the heater flap found at the rear side of your glove box.
To test the blend door actuator, disconnect the negative terminal of your vehicle’s connector. If your vehicle has a radio code, make sure to write it down, or better still, you might carry out a calibration.
You might decide to take your vehicle to a mechanic’s garage if you don’t have a calibration machine. If the heater is blowing cool air, the problem might be that you have a bum blend door motor.
When you observe the symptoms above early on, you should check the heater hoses. If the heater hoses are hot, that’s a clear indication, and you should fix the trouble.
Next is to locate the actuator; it’s mostly beneath the glove box, on or beside the heater box. You will be required to have an assistant who will switch the climate temp in various modes while you watch out for the movement.
If the blend door actuator doesn’t move with the climate temp switch for various modes, you have a bad actuator and needs replacing.
You also have to check your blend door and linkage; they can also cause the same issue if they are bad. If that is the case, you will need a professional.
How to replace a blend door actuator?
Follow this simple and easy guide, and you can avoid blend door actuator replacement costs.
You will only be paying for the cost of the part. For tools, you will need common mechanic screwdrivers and a 5.5 mm socket set, depending on your vehicle model.
#1. Remove the glove box or lower dashboard cover.
Take off the glove box mounted on the passenger side of the dash using a screwdriver or small socket set and ratchet handle.
The glove box mounting bolts are usually in concealed places; find them and unmount them to get them out of the way. Once you have all the screws that fasten in place unclamped, gently free the glove box or the beneath the dash panel.
#2. Extract the blend door actuator.
The actuator is mounted on or next to the heater box. Release the wiring clips with the screwdriver. You need to be gentle; these clips could be very brittle and could break. Once these are unclipped, depress the tab on the wiring connector and drag it off.
Inspect the connector for corrosion and rust, as this can cause resistance. Clean the connector using an electrical cleaner if need be. Now, remove the screws that attach the mounting screws to the actuator.
These screws are usually two or three in number you may require using a small universal socket to remove some that are placed in a concealed place. The actuator should now readily fall off, or gently wiggle to free it off.
#3. Turn the air door pivot.
Prior to installing the new blend door actuator, you have to turn the blend door manually to check that the blend door is not stuck, which jeopardizes the new unit. Grab the blend door, turning it in either direction.
It should turn freely to either side; if it’s hard to turn in full position, it could well be that there’s some obstruction that could put the new blend door actuator out of commission.
If the blend door is not moving freely, you’ll have to take out the heater plenum and fix it before you install the new actuator.
To check that you’re replacing the correct blend door actuator and to test door operation, turn the blower and work the blend door back and forth in either direction. You should feel a temperature change from the dashboard air vent.
#4. Compare and install the new actuator.
Place both actuators next to each other and compare them. Check if the wiring harness really is the same. It’s especially crucial to check here if you bought the part, as aftermarket parts are known to be different sometimes. If both actuators look alike, reinstall them.
Mount the actuator and stick the mounting screws in by hand. Gently torque the screws down with either a screwdriver or a socket set. Whatever you do, don’t over-torque it. Sometimes, the screws go into a plastic thread. As soon as you torque it down, socket the wiring connector.
#5. Reinstall the Glovebox.
Once you reinstall the blend door actuator, give yourself a moment of doubt and review your work. Reinstall the cover/glove box. Hand-thread all screws.
Important: Don’t tighten that first screw until you have screwed in the rest by hand; that one screw could make it tricky to screw in the rest.
Then, if all goes well, start the vehicle, flick the climate control knobs in different zones, and see if your labor bears fruit at last.
Final word
Understanding what a blend door actuator is, along with its workings, symptoms and timely repair will keep you from discomfort driving.
To recap, this article has detailed blend door actuator symptoms, how to test and replace, and should you decide you’re not courage enough to carry out.