Where is blend door actuator located on 2000 Yukon denail ?

the blend door (temp. control) actuator has failed. Try tapping on the actuator and see if air temp. changes. If it does, the blend door actuator is faulty. If it doesn't change, it still could be at fault but there is other possibilities. The blend door actuator is located behind the glove box here is a picture:

Front HVAC assembly:---

(1)Blower Resistor

(2)Blower Motor

(3)Blower Motor Connectors

(4)C230

(5)C203

(6)C204

(7)Temperature Door Motor

(8)HVAC Plenium