So the other day my air vents stopped working unless I put it on full blast. anyone know what this could be? I searched and didn't come up with a for-sure answer. Thanks

 

The blower resistor is most likely bad.

 

The blower resistor for sure.

 

X2

On my Camaro I had the opposite issue
the three lower speeds worked and hi didn't
there are two, one for the lower speeds and one for the highest speed (at least on a GM car)

 

What all three below the OP said. Its under your passenger dash; remove the resistor block and replace it with a new one.

 

On most imports that I've seen the lower speeds have resistors in a "block" (decreasing in resistance obviously as you increase blower speed) and HI is full resistor-less power; usually wired independent from the resistor block. It is still possible for individual lower speeds to die out however, despite them all being in a "block".

 

alright. thanks a lot guys. I'll be for sure replacing that this weekend.