Dash vents not working, A/C blows to the foot vents only

[FlatTwin]

Have not driven the truck in a bit (wonderful VP-44 puked again and no $$ to fix it!) but jumped in the truck over the weekend to move some big stuff around and when I turned the A/C on it worked fine but would only blow air out of the foot vents.No matter what position the climate control switch was in, air came out of the lower vents.Searching the bulletin board I did not find anything like this but did find several threads about the vent system being controlled by vacuum and if you had a leak that the doors would default to the floor vents. Any hints or suggestions on this? Thx,FT

[mopartechnician]

Actually if you loose vacuum the vents default to defrost just incase this happens and its snowing/freezing. I would take you hvac controller off and if you have a vacuum pump, try adjusting the doors with the pump. You might have a frozen door

[pepe]

The hvac doors are known to cracking or breaking. The doors then get stuck in one position. Mine did this and then I was only getting air at the foot vents. If it is the doors it's a bit of a pain in the rear to fix, with the dash coming apart.

[Mopar1973Man]

I've seen vacuum lines damaged by mice, vacuum motors damaged by BB's from a air rifle, I've seen vent doors stuck because of a 1 dollar bill wedged in the door, the list goes on... You might take some time and look under the dash for common vacuum issues first but worse case your pulling HVAC box out.

[flagmanruss]

The blend door is on the passengers side over the foot well, electric controlled... that's the WRONG one. The one you want is over the hump, vacuum controlled, next to the driver's foot. Sometimes you cam flip it by hand but like has been said if the vacuum is cut off, it goes to the default DEFROST setting. My control is frogged up & I'm putting it off because to work on the control or door requires moving the dash back. I had a nephew with long arm move mine & it stayed until I started the truck again. Now I suppose it is possible, though rare, that the in dash selector could go bad (accessed by removing the dash trim) but I really doubt that'll solve it.

[CTcummins24V]

Have not driven the truck in a bit (wonderful VP-44 puked again and no $$ to fix it!) but jumped in the truck over the weekend to move some big stuff around and when I turned the A/C on it worked fine but would only blow air out of the foot vents. No matter what position the climate control switch was in, air came out of the lower vents. Searching the bulletin board I did not find anything like this but did find several threads about the vent system being controlled by vacuum and if you had a leak that the doors would default to the floor vents. Any hints or suggestions on this? Thx, FT

X2 on checking dry rot on vacuum lines (rubber elbows or 90s) or disconnected lines. I had dry rot and the air system did not work and 4x4 would not work either. Follow line from vacuum pump/power steering pump.

[FlatTwin]

Well guys,An update. I poked around the engine bay while putting a new VP-44 on the truck (second one in 15 months! Grrr) and found two vacuum hoses rotten. Replaced them and now the vents in the cabin work great!Thanks for the help everyone and thanks Michael for this forum!FT