Do any of you fine forum members happen to have a break down of the HVAC assembly for a 2000 C/K with out duel zone temp controls? I need to replace the blend door actuator on my neighbor'* truck and I can't remember if its the one on top or the bottom of the heater box. I'm hoping it'* the bottom one because I don't feel like ripping the dash completely apart.

http://gmsi.gc.maricopa.edu:9001/si/home.do

Thanks Justin! Your just a plethora of info.

Justin, I'm a new member here. I have a 2000 GMC Yukon XL 2500 SLT. The airflow in the AC/heater will not change locations. I believe it is the blend door actuator. I have tried the instructions to "initialize the actuator." I heard things clicking around as though it was adjusting and resettting but it did not fix the problem. The airflow just blows where it chooses. It is currently in the defrost location but will change intermittently. Any ideas?

sounds like the position actuator gears are bad, though i havent taken one of those trucks apart to tell you exactly how. pretty common failure it will have to be replaced though just resetting it i doubt would do anything. you can watch them and one should move when you change positions if so the controller should be fine

Nothing happens when I move the controller. I've heard there are a couple or more actuators...do you know by chance which one I would need to replace?

if nothing happens it might be the controller, i thought you said you could hear clicking or banging

Oh sorry, yes I hear things moving and trying to adjust but it doesn't change the airflow direction. It might be the gears...so you're saying to get down and watch during that re setting process and I should be able to see something?

the rod sticks through the actuator and you should see it turning