Air flow will not change from dash vents to defrost

[SmokeEater829]

1989 Bronco II. 2.9L 5 speed 4x4.

A/C works and blows cold. Heater works and gets hot. Only problem is, the air only comes out of the dash vents. I cannot get the the air to come out of the floor, or defrost/winshield vents. What do I need to check? Not concerned with the floor vents, but I need the defroster to work. Frozen windshield in the morning sucks!

 

[srteach]

if I remember correctly, check the vacuum source. That is what changes the position of the blend door. Then check the blend door linkage behind the glove box.

 

[SmokeEater829]

I'll check on the blend door. I noticed that the slide switch is kinda hard to move so I guess I need to check on that too.

 

[SmokeEater829]

Blend door is working fine. Must be a vacuum problem. Waiting for my EVTM to get here. Hopefully that'll help me out!