It is controlled by a blend door actuator which is a small electric motor.
Vent air door actuator.
First the electric motor can burn out rendering the unit non responsive so nothing changes when the temperature or.
When one of these stops working you may either get cold air but no hot air or there will be hot air with no cold air.
Air door actuator replaces 15 73952 52495593 89018374 604 112 compatible with chevy gmc cadillac hummer 2003 2014 models hvac blend control actuator air heater blend door 4 5 out of 5 stars 392.
604 106 heater ac fan air vent blend door actuator for silverado gm pickup truck.
Also called hvac actuators these small electric motors control the flow and blend of hot and cold air to the passenger areas by opening and closing the vent doors that let the air through.
Compatible for 1999 2012 chevy silverado 1500 chevy silverado 2500 hd chevy tahoe gmc sierra 1500 1997 2005 buick century 2002 2014 cadillac escalade 1995 2003 oldsmobile aurora 2003 2009 hummerh2.
Hvac temperature blend vent mode door actuator for dodge ram 1500 2500 604002 us.
An actuator can go bad in of two ways.
A blend door actuator is made up of an electric motor that turns a plastic gear set in one direction or another which is connected to an air control door pivot at the final drive of the unit.
Heat heater a c ac fan air vent blend door actuator for cadillac gmc buick us.