The piece that controls airflow for the Heating / AC......I believe mine is broke b/c when i have the air on it comes out all vents no matter what setting its on. Im trying to buy from LMC truck but i dont know the "official name" lol

 

HVAC Control Check that the back of the ***** havent just worn.

 

would a worn **** cause air to come out of all the vents?? also, i can hear a hissing noise behind the controls. like the valve is broken or a vacum line came disconnected

 

You should check to see where the vacuum leak is.

The HVAC control module (non-automatic temperature control) houses all of the vacuum routing to the specific actuators under the dash.

 

Sounds like you have a unplugged vac line or one with a hole in it. That would cause air to come out all vents as well as the hissing.