for the last week my truck has no heat coming out the vents on the drivers side.but on the passenger side it has hot heat coming out and if I put the heater on the floor it has heat.what would be causing no heat to come out on the driver side vents?

 

You have blend door failure. Tons of threads about this problem here. Do a search, you'll find all the help you need.

 

Not necessarily. In my case it was a bad heater core.

A blend door issue would ONLY apply on a dual zone system. Unless you have dual zones it's not a failure of the door, because otherwise you would have no heat on both sides.

Here's what I found when I tore my HVAC unit apart

AC Evap (new and old)



Heater core (note the leak)


New parts in place. This photo shows the blend doors in question. On a single zone unit those doors are on a fixed shaft.

 

The 'blend' door - damper, allows fresh air to either go thru the heater core, around it, or mixes it. This one is roughly behind cup holder thing, but farther to the right
the damper - or actuator that may have failed is on the left, kinda behind the ashtray, that modulates air between the floor and vents.
on a single zone, the dampers that direct air to either side of the cab are linked together; this one is inbetween the two mentioned above
As was stated, do a search. There is alot of info here.