I cannot feel air coming out of my air vents, even with the fan on high. I can feel air coming out of the heat duct on the floor. What could this be.

 

Sounds like a vacuum problem. Could be a valve in the vacuum system that switches the positions over for the air to discharge. I had a problem like this with my car and the valve was cheep but labor was expensive because the whole dash had to be removed to access it.

 

thanks, I was afraid it would entile major work

 

what year truck?

if you can find out what is wrong, get a chilton book for your truck, and you can probally do it yourself for the price of the part and the book, which is about 10-15 bucks.