My buddy stopped by with this problem tonight. After reading this wonderful post, and examining the excellent pictures, I had to see if I could get him safely on the road with defrost on these Michigan mornings.
From the passenger side floor (with flash light) look through the floor vent. At a distance of about a 1 1/2 feet you can see the vent door. My friends was laying down as to close air flow to the floor vent. I took a lenghth of welding rod and gently pushed the vent door up. When I did this I could feel a little resistence. The door acuated and stayed in the up position and the floor vent worked as well as the defrost.
Of coarse, not leaving well enough alone, I messed with the selector switch, which then shut off the defost, and only the floor vent would work. So I started over from the beginnig by putting a 90 degree bend on the end of the rod so I could pull the vent door down again, and then push it back up like I did the first time. Again both defrost and floor vents worked. So I sent him on his way until I have time to fix this for good .
My truck is a 99 ctd and I had to do this proceddure to fix my evaperator core. The worst part is trying to disconnect the 3 wiring harnesses.
