most fords have bad design blend doors. that cause your heat to stay on cold or stay on hot. it cost up to 1400 dollars to fix at a mechanics shop. by going to this link, [www.heatertreater.net] you can watch a video on a easy fix for this problem. they have the video and part for sale for 119.99, or you can buy the blend door itself for around 20.00 dollars. but no video. its worth your time and money to check out this web site. most anyone with some mechanical ability can fix thier truck themselves,from one ford truck lover to all the others, wheelhorse R/N [edward]