need heating help
 

a friend has an '84 300td and he can't get any heat through the floor vents under the dash.he can get heat at the panel vents and defrost but not at the floor.i told him it sounds like a vacuum problem with the directional doors.i did a seach and found a mention of a valve misfunction-monovalve.where is this valve and could it have anything to do with his heat?

Sounds like it's the vacuum servo for the footwell vents. Remove the kick panel under the driver's side dash. To the right of the accelerator behind the heating ducts is the servo for the footwell vents. Put a mighty vac on it and see if it holds vacuum. When mine failed it was a leaking rubber connector between the plastic line and the servo itself.
Dont mistake the defrost servo for the footwell servo. The defrost servo is on the side of the ducts about a foot in front of the accelerator.

success!!
 

thanks for your direction,kerry!i just talked to my friend and he told me all is well now.turns out the servo wasn't the problem.i'll go into detail a bit for the benefit of others.the footwell servo is controlled by a solenoid,that is connected to the floor switch on the control panel.there are three solenoids in a row,all controlling one function or another.to check the panel switch,he disconnected the lead from the solenoid for footwell and put it on the second solenoid and press the button and it activated that function-so switch is fine.he then switched solenoids(#1&#2)and this cycle the footwell as it should.so footwell servo is fine but solenoid is kaput.a while back he disconnected his a/c.so i suggested that he swap the solenoid #2(this one is for a/c) for #1 and everything is peachy.thanks for all your help:)
for those of you reading this i hope i made it easy to understand.if it makes sense to me i'm sure all of you will have no problem!