Heater stuck blowing hot air

[wooner]

What controls the temperature knob on the heating controls? No matter where I turn the temperature knob, it blows hot air. It has been sticking for a while, but if you go from hot to cold a couple of times, it would start to work. This morning, I could not get it to blow anything but hot air no matter what I did.

 

[JLDickmon]

the actuator on the blend door is most likely toast.. behind the glovebox, red or white, about the size of a pack of smokes...
start the truck and flip the control back & forth in about 5 second cycles... see if the actuator motor keeps up... I'm betting it doesn't..

 

[wooner]

I found the actuator. Disconnected the wire harness, plugged it back in, now it works fine. I love fixes like that.

 

[Arisley]

Take it apart again and spray some contact cleaner in there. Button it up, good for 12 more years.