Hot air constantly blowing through floor vents, drivers side only?

[baglie1]

Hot air is constantly blowing through the drivers side floor vents, even with the climate control system off. The amount of hot air flow varies with speed. Ideas? It's SUPER annoying lol, especially on 100 degree days!

 

2012 GMC Sierra 1500 SLE

[dna9656]

Prolly diaphragm bellows rotted out. Given the age of your truck.

[davester]

are the heater controls set for hot or cold air?

 

If it's set for hot, and say, to get air from outside the cab (vs recirculated air), even w the fan off, air will get pushed through the hvac system, over the heater core and into the cab.  Switching it to cold will reduce the temp to whatever it is outside. Switching to recirculate mode (which may mean switching to vents or whatever, read your owners manual), will reduce the amount of airflow through the hvac system.

[davester]

And  there aren't any "bellows".  There are solid  plastic doors the actuators move, which largely seal just by themselves, and then have a strip of foam around the edge to better seal the door. The foam does deteriorate over time, but this is unlikely to be a significant cause of the problem.

[baglie1]

Even set to "recirculated", the air pushes out and is hot. I have noticed that sometime it doesn't want to switch between recirculated/vented air. Say it is set to Circulated Air and I want to switch to Vented, when I click the Vented button, it just quickly lights up/clicks and immediatly switches back to Circulated. It's done this a few times now. So maybe it is an actuator getting stuck? But then, that doesn't explain the hot air when everything is off does it?

[davester]

read your owners manual.  there's only a few specific modes where recirculation can be turned on, and it automatically switches to fresh air if you change to the hvac to a mode that doesn't support it.