tahoe ac question

2001 Tahoe question manual control heat and a/c some days works fine other days stuck on high heat no matter where the controls also a/c compressor cycles when in heat position not defrost any help would be great

Sounds like temp door actuator is inop or stripped. See if you can locate it either above gas pedal or in behind glove box- and see if it moves when commanded.

temp door above the rug on top of the tranny hump in the venting box.. put two washers to set it out from the venting box then the door will move easy