Vent always blows hot air

[swaybarz]

2001 silverado

The vents always blow hot air no matter the temp is set to and regardless if the fan/ac is on. This problem just began. Any ideas out there would be greatly appreciated. Also is this a dealer only issue or can any old mechanic fix this if I can not? Thanks.

[2000 Silverado 4x4]

It's funny my 2000 does it too every once in a while. Sometimes if I have the heat on and I try to turn it to vent or cool it stays hot. Regardless of what I do it will blow the hottest air ever! The only "fix" is to turn the truck off for a while, gas station etc, and when I turn it back on it's okay. My old man (a mechanic) said he assumes, without looking into the problem, that one of the vents/flaps is sticking in the dash. Dunno, hope you get some help

[swaybarz]

I think you may be right about it sticking...it was fine this morning and was still blowing cool air through the vent after the truck got to normal engine temp. I also heard something moving behine the glove box area when the truck was turned on....I hope this is a seldom problem and I sure hope it never stays stuck.

[B18B_EG6]

i got the same problem and it just gets worse. it only did it a few times and now its every day

[chuck16]

I remember reading about this kind of problem a while back. Mine has a problem adjusting to cool. It's mostly Hot and like the lower 1/3 is only a cool adjustment.
I remember somebody mentioning something about a "Heat Modulator" or something like that? Sounded like something under the dash in the ducting system that could be replaced but, I wasn't sure where to look or whether or not it was functioning correctly.
Don't know if this helps....