Car Heat Blowing Cold Air? Tips to Check the Blend Door Actuator

If your car heat is blowing cold air when you try to turn it on, there might be an issue with the vent door or the blend door actuator. Find out how this can cause this problem, how to fix it, and other parts that can leave your car blowing cold air when you turn on the heat with these tips in this video from our expert mechanic Andy.

Car Parts That Can Cause the Heat to Be Blowing Cold Air

Mechanic in a car with the heat blowing cold air sitting next to a blend door actuator

Maybe the heat in your car is only blowing hot on one side and cold on the other or it’s not working when turned on. You might also hear a clicking noise from behind the dash vents when you try to turn on the heat.

Bad Blend Door Actuator

Blend door actuator connected to a heater box
Blend door actuator (left) connected to a heater box

If you hear a clicking noise inside the dash along with the heat not working, most likely the problem is the blend door actuator. Blend door actuators attach to the heater box. The heater box is located below the dash and houses parts like the blower motor and heater core.

The blend door actuator opens and closes the blend door in the heater box. The blend door helps direct airflow when you turn the AC or heat on. If there’s a problem with the blend door, that may also cause the heat to not work in your car.

Sometimes you can access the blend door actuator from beneath the glove box. They are attached by a few screws and an electrical connector and are usually easy to replace.

Bad Blend Door

Blend door knob
Blend door knob

After removing the blend door actuator, you may find a broken knob that controls the blend door. You can turn the knob and listen for the blend door inside the heater box moving. It should open and close as you turn the knob. If the blend door is stuck, the knob won’t open and close the door but spin in place instead. The knob should also not be loose where it can be pulled in and out or up and down. If this is the problem, replacing the blend door actuator won’t fix it.

Heater box with blower motor (left), evap core (center), and heater core (right)
Heater box with blower motor (left), evap core (center), and heater core (right)

To fix the blend door you’ll need to have the refrigerant recovered by a professional since the AC evap core is inside the heater box. You’ll also need to remove interior components to access the blend door, like the dash.

More Tips for a Car That Is Blowing Cold Air with the Heat On

Shop Quality Auto Parts

Fix a car blowing cold air with the heat on yourself with quality auto parts and tips at 1aauto.com
Summary
Car Heat Blowing Cold Air? - Tips to Diagnose & Fix - 1A Auto
Article Name
Car Heat Blowing Cold Air? - Tips to Diagnose & Fix - 1A Auto
Description
If you have a car with the heat blowing cold air or the heat blows cold air on one side, find out how to diagnose and fix it yourself with expert tips from the mechanics at 1A Auto
Author
Publisher Name
1A Auto
Publisher Logo

Leave a Reply

Your email address will not be published. Required fields are marked *