i have a 2001 f150 with the 4.6. I was driving down the road when all of a sudden my ac started blowing through the defrosters when id accelerate and then switch back to the panel when going at a constant speed. I checked the vaccum lines and nothing is disconnected or cracked. And now it will only blow hot air through the defroster all the time. Still no cracked or disconnected lines.

 

Keep looking for a vac leak because that's the problem.
For those year vehicles it is common to have vacuum leaks in the evap lines behind/below the battery box.

 

ooops! Thought this thread was about kingranchcoy!

 

Get it together

 

so i should only look around the battery box? it wont be anything into the dash? I dont know much about this stuff

 

Behind the battery is the most common, but not the only place you should look.
I believe there is an O-ring in the HVAC controls themselves that goes bad.

 

There are hard plastic vacuum lines behind the battery that get brittle and break.

 

how much am i looking at spending for either the lines or the o-ring? possibly if a shop since i dont have much time anymore

 

Broken lines behind the battery are usually easy, you can cut the bad section out and splice with standard vacuum hose. Cheap and not time consuming.