a.c heater help

[woody367]

I have a 99 Yukon, when you put the a/c or heat on it come out the spot it is set to but also the defrost. Change to just defrost and it only comes out there like it should but put it to the floor or dash and it come out there but also the defrost. I checked the motor under the dash by the gas petal and it moves freely. And Ideas?

 

[Slammed]

It sounds like the blendoor actuator

 

[lesterl]

Mode section is screwed up, that unit uses one actuator to run 3 dampers and suspect binding in one of the spring loaded arms, this is the actuator by the gas pedal.