I'm having trouble with my heater vents.
when i use my a/c it only blows cold air out the two left vents and there is hot air blowing out the two right vents.
I'm assuming its my heater control flaps/doors??
anyone know how to fix this? is it a vacume issue or??

 

What year truck are we talking here? I'm going to assume you have the Electronic dual zone climate control? If so then yes it's most likely your passenger side blend door that's crapped out. On a 2008 F250 this is located behind the glove box.

 

Sorry, it's a 2008 F350 SD with dual climate control.