Why is my defroster stuck?
What Goes Wrong? Heat, extreme cold and vibration of the engine and car’s suspension can cause component of the defroster to fail. In some cases an electrical motor can burn out or the gears inside the actuator can break causing the defroster door to get stuck.
Why does the AC come on when I use the defroster?
Your air conditioner (whether it’s set to cold or hot) condenses the moisture out of the air into water. The system then pumps dry air into the car. When you turn on the defroster, it pumps dry air up toward the windshield. This helps to evaporate the moisture.
Where does the vacuum line from the defroster go?
Vacuum lines travel from the vacuum control switch on the dash to vacuum servos under the dash. These servos move the air doors which turn on and off the defroster. If you can hear a hissing sound when the car is running from under the dash then vacuum is escaping.
How does the climate system control the defroster?
The climate system is responsible for controlling the position of the defroster actuator which is connected to the air position door in the heater plenum. This actuator controls defrost, middle and lower air vents. When it fails it can do so in the defrost position and must be replaced.
Why is my HVAC vent selector not working?
I have an ’02 TJ X and am having trouble with my HVAC vent selector. It will not switch into upper vent mode, only have the option to have it all on my feet, or feet and windshield. I searched but didnt find any real solutions. Help?
Why does my defroster fade when I go up a hill?
A defroster can also fade when traveling up a hill but then return once the grade is overcome which is a signal the vacuum check valve has failed. If you are not sure which kind of system you have either vacuum or electronic any car made after about 1995 has an electronic system with no vacuum controlled vent door servos.