heat stuck on high
 

Hi guys,GREAT site. have owned several gmc and chevs in the past, and just sold my 2004 dodge 2500 Cummins and downsized to a 2000 Z71 Silverado. Am happy to be back in chevy land again. I am sure i will have many questions for you, but i have one issue I need to resolve (before i melt my interior).
My problem is that approx 75% of the time when I select the temp control to max heat, it stays there.
No matter what i do it wont move the actuator or mixing door out of the full hot position. The only thing that seems to work is when you shut the truck off, and cut off all electrical power by opening up the door.
This is a little difficult while going down the freeway. All other functions of the controller work fine. IE,
recirc/fresh air, fan speed, air position selector (vent/ defrost/ floor heat etc).
With the Ignition on and engine not running, when the unit is malfunctioning, when i attempt to turn the temp selector from hot to cold, i cannot hear any door operation at all. but i do hear the actuator working or functioning the rare time it does work (if that makes any sense). and when it is working the running time of the actuator seems to be normal, and doesnt sound like it is labouring or jamming.
My initial thought is that the electrical controller componant is faulty. Am i on the right track here?
Any trouble shooting tips here would be greatly appreciated. I have a Haines manual but as is often the case, it is not much help here. I am currently looking for a GM shop manual for it.
Not sure if it matters, but it is a 2000 Z71 LT with A/C with the 5.3V8
Thanks again guys!!!!!

RE: heat stuck on high
 

Does it torch out of both sides,or just !?

RE: heat stuck on high
 

it is hot from all vents,or both sides if you wish. It does not have dual climate controls.

RE: heat stuck on high
 

Most likely,a bad hvac temp actuator..its on the case,by the floor hump...look down there and see if it moves when commanded with the knob.

RE: heat stuck on high
 

how would you tell if it was the actuator or the electronic controller itself? i have not looked for the actuator that you mention, however i can hear it move when the system is working. when it is stuck on high heat, and i turn it cold, there is no sound at all (this of course when its not working). So once again,
if nothing is moving, IE, no actuator movement, could it not be either the actuator you mention or a tempermental electronic controller?

RE: heat stuck on high
 

You need a voltmeter,to see if the command is getting to the actuator.
I'd say the odds are 70/30 is the actuator

RE: heat stuck on high
 

Great, thanks for the info......I will check it out and let you know!!!!