I have a 1999 ford f 250 super duty 5.4
extend cab 4x4

i have had the problem for a while i figured it was a vac problem i i went to track it down and found that the spring loaded vac level that contols the door to send the air to the defrost or floor or vents the spring was broken i got that replaced and i still have the problem that all the air is moved to the defrost and also have the problem with the heat to not just ac . when truck idles then the air flow goes to the right spot so i really think it is a vac problem just tried to track down all the vac lines and have not had any luck with finding a leak is there a part that maybe be causeing the problem instead hope someone can help me out
thanks alot
and u can email me if u want bakerracing@bright.net

 

i see about 50 people have looked at my post with out any replys is it that i need to give more info let me know

 

Have you checked the lines behind the battery on the passenger side?

 

yes i have
not saying i have checked all the lines 100% because i do not have a tec sheet showing me where they all are but i have worked on it for hours and come up with the same thing that they are all good. if anyone has info that tells me where they all run and how many there are i will use it to track them all down that would be great

 

still hopeing someone has a idea please help