1997 Dodge Dakota

On ac setting pop the hood and feel the ac lines. Is any of them really cold?

Well it sounds like the ac is working good. And with the dash mode door blend doors not working definetely would be checking to make sure the vaccum lines are in all good shape and properly getting vacuum

Well the vacuum lines connect to motor at the back side of the switches for the hvac system. And you can test for vaccum in and out of it. But you cant test if the blend door is working or the solenoid is shot or if the vac line is damaged inside the dash unless you strip it down

That is unless you want to take a vaccum pump and try to move the doors that way to see if you got blend door action

The panel that contains your fan speed, air temp and mode.

black line is 8inch of vaccum on those ports.

and the white is vented. each position is labled underneith

Do you have vaccum coming to the switch?

Now were getting somewhere.

There should be a black vaccum line under the hood that runs from brake booster check valve or intake manifold fromt here it runs through the firewall by the heater core hoses. Check for vaccum coming to the line there. Before the checkvalve and after. If you have vaccm there the restriction or a leak in that line.

So the vaccum line that goes throug the firewall. The black one. Has vaccum up to the firewall. But where it connects at the switch has 0? Must be restricted

Yes or run a line from the brake booster to back of switch and everything shoudl work then youcan drill a hole in the firewal to put in new line if you want or you can pull the old one out and thread in new one. But there has to be something wrong with that line if you have vaccum up to firewal but none to switch