Thermostat Control?

I've got an 01 Z71 ext cab 5.3 and here recently I seem to have problems getting the temperature in the cab cooler. It is like it is stuck in heat mode. Every once in a while it will go to cool but not everytime. And with the thermostat stuck on heat mode it won't allow the A/C to kick on. This is fine now since it is cold outside but come summer time it could be a different story. Could it be the control in the dash? any suggestions? I just have the turn knob in the dash, no dual climate control, no digital.

The thermostat is part of the engine cooling system, and other than keeping the coolant at s specific temperature, does not affect the operation of the HVAC system.

It sounds like your problem is more than likely the temperature blend door actuator, or the controls. Look at the actuator and see if it moves, if not, make sure it is being "told" to move.

I realize that there is a thermostat on the engine that opens and closes based on certain temperature allowing coolant to flow through the block. I am talking about the control in your dash to make hot or cold air come out your vents usually next to red and blue colors and also next to the control where you want your air to come out.

I understood what you meant, I only said that so you'd know the actual name when testing, ordering parts, or possibly talking with a servicewriter. Miscommunication of a part can cause headaches for everyone involved.

The second paragraph of my original reply applies to your situation.

Thanks, I'll try and trouble shoot starting at the control knob.

I have replaced both the control head in the dash and also the temperature blend door actuator. I checked the continuity between the clip for the actuator and the clip on the back of the control head, and there is no short in any of the wires. Doing this I know that the wires for the actuator go directly to the control head. I also disconnected the battery to reset the computer. What else could it be?

I have replaced both the control head in the dash and also the temperature blend door actuator. I checked the continuity between the clip for the actuator and the clip on the back of the control head, and there is no short in any of the wires. Doing this I know that the wires for the actuator go directly to the control head. I also disconnected the battery to reset the computer. What else could it be?will this help http://www.automotiveforums.com/vbulletin/showthread.php?t=500794&highlight=heater+stuck+on

Plugged Heater Core? Oddly enough when I changed the Water Pump in my truck and I changed the Thermostat at the sametime; my Temperature mix was far better in the cab than it's been the entire time i've owned the vehicle.
Weird, Yes. Does it help, Probably not but, I just thought I'd throw my :2cents: in.

I replaced the actuator with an aftermartket one from O'reilly's. Should I get one from GM instead? From the thread (URL) sent from muff34 it sounds like other people have had the exact same problem that I have. Has anybody found a fix for this. I have already replaced the control head in the dash.

I replaced the actuator with an aftermartket one from O'reilly's. Should I get one from GM instead? From the thread (URL) sent from muff34 it sounds like other people have had the exact same problem that I have. Has anybody found a fix for this. I have already replaced the control head in the dash.

from what i have read you have done everthing but check for a binding door in the duct work. use mirror and if possible see if debris is causing door to stick in the heat mode........also i believe you have the manual temp control, not automatic temp control?

Well I didn't have a choice and had to take it to the dealer. They said that the actuator was good and that they had to go into the computer and manually reset it and then recalibrate it so the control head in the dash could tell the actuator where hot and cold was. Now whether or not the control head was actually bad I don't know but they said that that was probably the case and they reprogrammed the new control head.

For the previous reply, I had taken the actuator off and could manually turn the blender from hot to cold and there was nothing sticking. I had to do this cause it got stuck on cold which stunk cause it is 0 degrees outside.
Thanks for all your help.