MOCA 604-113 HVAC Blend Door Actuator Fit for 1999-2002 Chevrolet Silverado 1500 & 1999-2002 GMC Sierra 2500

The actuator is responsible for moving the air direction and temperature doors inside the heater plenum, their job is to manage mode settings. If the air conditioner blows hot air or the heater blows cold air, there is a problem with the Blend Door Actuator.

The electric motor can burn out rendering the unit non-responsive so nothing changes when the temperature or vent mode controls are moved. You have to check the Blend Door Actuator.

The plastic gear set will become brittle and break which will sometimes allow the unit to work while making a ticking or clicking noise and then stop. When you notice abnormal noise, you need to check whether there is a problem with the Blend Door Actuator.