I have a vacuum line under the dash diconnected

that would be the blender door accuator

Your controls are vacuum operated. Make sure that there is vacuum present...if not find the disconnect. Or, the vacuum "motor" that controls air direction has failed or is stuck.

Most likely either the vent switching mechanism is dirty and won't switch the flaps -or- most likely the vacuum that is used to turn the vent flaps is either leaking and not pulling enough vacuum. You will have to get underneath the dash near the center, to check and see if you can manually move the vent flaps. If so, then most likely it is a vacuum leak in a vacuum line to the flap mechanism.

you bled doors are not working, could be a broken vacuum line, vacuum line fell off or one of your actuators is not working, you would have to look under your. dashboard to check these, see if you can move your actuator

ck for vacuum leak under dash by drivers side fire wall, and under dash .the defrost floor setting is default when system has problem.

Vacuum supply starts on the drivers side of the engine. There is a vacuum line going into the brake vacuum assist from the manifold. branching off of that line is a double line that snakes under the intake manifold, behind the valve cover, along side the valve cover on the passenger side headed to the front of the engine. Then it curves to the right side of the engine. One set of hoses from this line goes to a valve control (red and green i think). The other line goes to the vacuum storage ball, it should be black. The vacuum circuit continues out of the ball in another black line that snakes into the firewall. It goes under the heater core black box and disappears under it. Now go into the passenger compartment and drop the glovebox. look to the back right you will see a black and a white vacuum line coming out of the firewall. The black line is your vacuum supply from the engine. It goes up to a little rubber manifold. disconnect the lines coming from the dash switch and check for vacuum on the manifold where the black line is going in. The white line controls the cabin air intake under the glovebox and the thermostat shutoff under the hood. It should only have vacuum when the switch is in a certian position, AC probly. The other three lines coming off the rubber manifold snake behind the dash vent door assemble and come out near the gas peddle. The red one controls the dash vent. apply vacuum to the red hose and see if the vents go to the center dash position/AC. The yellow and blue? ones control the floor vent control near the gas peddle. yellow gives you half floor and half defrost. blue gives you all floor. you can use a small vacuum line to connect the black vacuum supply to each individual line on the manifold and check the function of each vacuum control assembly individually. I hope this helps. On my truck each control unit works fine when i apply vacuum to them individually but when I hook the dash switch up to the rubber manifold it goes to defrost. I tried changing the dash switch and the lines running from the switch to the rubber manifold and the vacuum ball under the hood, nothing works. I suspect I may have leak i just haven't found yet. next step is to get a vacuum gage and start checking the amount of vacuum i am getting at each vacuum line. I'm sure it is supposed to be getting a specific amount of vacuum and will not work if the vacuum drops below a certian level due to a leak in a line somewhere? God bless.

I really can't be sure off hand, but what you wrote looks like the control valves are sticking(these flaps allow air to go different directions at the vents). its located at the heater core(towards the left side of the heater core) under the plastic just under the dash. you can manually move them, encase they are stuck, they do stick sometimes. while checking the vent doors, make sure your vacuum lines are connected. also check to make sure your vent hoses are tight. I hope this helps

either no vacuum is getting to the vent door switch or the vent door switch is bad, but I suspect the vac hose is diconnected, or cracked. under the hood the line goes into the dash to work the doors, make sure its got vacuum to it when engine is running., or there is a vac leak

u have a loss of engine vacuum to the dash control that moves the actuators that change the air flow around to the diff locations of the dash. Start at the engine supply hose and work backwards, the vacuum line comes in on the passenger side from the engine bay, it is under the dash along with other plastic vacuum lines the supply line is black, u will need a MITYVAC brand tester to check the vacuum supply to the diff vacuum actuators in the dash.

the idea of the switch is run on vacuum and is not making contact with the switch it self either worn contacts in the switch itself **** as an obstruction as well or the vent door is stuck in just that position either behind the glove box or the ash tray are the vacuum lines one of them may be pinched off or the door needs a bit of help until you can free it up