I have a 2002 Lexus Gs300. When I turn on
the heat the driver side and backseat vents
blow cold air, but the passenger side vent
blows hot air. What could this be?
The ductwork has blend doors that move to get the temperature to the vent where you want it. Could be that one of the blend doors is sticking because the door actuator is defective. You may have noticed a tapping sound under the dash from a defective actuator. The doors are located under the dash; possibly behind the glove box and above the accelerator pedal. The actuators are small boxes that probably need replacing. For most people, it's not an easy fix and you probably need a mechanic to do it.