I've got something backwards in my vent system....

[Mattchu60]

So I recently completed my restoration of a 87' C10. Out on the road testing and noticed the vents are "backwards".

When I put the air system to "vent" it pushes all the air to the floor ducts. When I switch to "heat" it pushes the air to the dash vents.

I'm pretty sure thats not right. I'm stumped on what I did wrong here. I did put a new heater core in so I had to remove some of the heater door parts, but I thought I got them back together correct...but maybe I didnt?

Anyone got an idea on this one? Could it be that the vaccum lines are backwards somewhere (I dont think so....only really can connect them in one spot).