Easy tips

Why are the top vents on my car not defrosting?

Why are the top vents on my car not defrosting?

If the actuator is electronic, then check for power to the actuator. If there is power and a ground circuit, then the actuator needs replaced. If you need further assistance with defroster not working on top vents, then seek out a professional, such as one from Your Mechanic, to help you.

Why are the vents on my Chevy Silverado not blowing air?

OK, trying to help my 82 y/o Dad figure out a problem he is having on his 2001 Chevy Silverado. The dashboard vents will not blow any air but the defrost and floor vents work fine. Not a blower motor issue, can be heard running.

Why are my dashboard vents not blowing air?

The dashboard vents will not blow any air but the defrost and floor vents work fine. Not a blower motor issue, can be heard running. Thought it could be a blin door issue but that seems to be more related to temperature control than what vent the air is discharged from.

How does the air vent work on a defroster?

The vent control system for the defroster in integrated into the operation of all temperature controls and uses forced air provided by the blower motor. On newer cars the vent direction and temperature controls are operated by a series of 3 or 4 electrical actuator motors which are adjusted by the climate control module.

What causes air vents to stay in defrost position?

If you have an older car then the defroster system is controlled by using vacuum supplied by the engine. Lift the hood and inspect the vacuum hose or tube that leads from the intake manifold to the passenger’s side firewall. The image below shows a typical line break which causes the vents to stay in the defrost position.

Where is the defroster located in an air conditioner?

The defroster is part of the heater and air conditioner system which is housed inside of the heater plenum. The vent control system for the defroster in integrated into the operation of all temperature controls and uses forced air provided by the blower motor.

Why is my defroster not working on my car?

A control switch on the dash can fall apart allowing the vacuum to escape and not reach the servos. 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.

Why do air vents need to be replaced?

Actuator Replacement 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.

Author Image
Ruth Doyle