Heat only coming from dash vents, no defrost?

[VTPSD]

On my 91 ecodiesel jetta, I suddenly lost the ability to get heat from anything from the center vents (below stereo and the vents by the driver and passenger doors). I cant get it to blow from the defrost or the floor. When I play with the selector I can hear some noise and once in a while the defrost will come on, but then i can hear the door move a bit and its back to the center vents. My vac pump appears to work well, I checked the vac line that runs into the AC and it holds vacuum. Do I need to pull my heater box apart? Maybe something broke wit the flap? Not sure if this is a common issue with these things.

[VTPSD]

i should also add that the heat that does come out of the vents is very hot, and everything was working perfectly until just yesterday, so i dont think this is a foam on the flaps issue...

[TylerDurden]

There are a couple of plastic gears under the front of the airbox, by the vent/def-floor dashpot... maybe they are jammed with debris. You can see the gears & linkage easily with the console removed.

[VTPSD]

i will give those a look first, thanks. Does the vacuum selector above the temp control ever go bad? Not even sure how i would test that.

[TylerDurden]

I imagine it can go bad.

The "normal" position for the vent damper is in the defrost-floor position, so you might try running the system with the vacuum disconnected, to see if the air goes the up to the defrost outlets.

[VTPSD]

thats a good idea..strange that mine has seemingly defaulted to vents. I can clearly hear something moving when i switch the heat on and off, is there a second vac actuator that could still be moving, perhaps for fresh air vent?
I will check it out a bit more tonight and report back.

[williamtaygan]

Do you have a Bentley? There are three (Four?) vacuum actuated flaps on the 91 Eco Check and make sure these are all moving at the proper time. If there is a vacuum leak, they will not move from the default positions. If those all work, you may have a chunk of foam stuck inside?  I had a problem with my 91 Eco not moving from the center to the defrost. But not with the heat/cold.  I just started parting out my 91 eco, so I might be able to help you out if you need something.

[CRSMP5]

imo foam fell off... defrost is default.. max heat is too.. but heat is the "bpttpm gear" i think on bottom of box.. been too long since i screwed with one.. if it moves with no temp change.. foam gone

[VTPSD]

i can change my temp no problem, goes from cold to very hot just like it should, just cant get it to blow out of defrost or floor. I was messing with it on my drive to work this morning, and all of the sudden it selected defrost..then i moved it to floor, and to floor it went, then i hear something move inside, and its back to vents only. Strange. Hoping to avoid pulling the heater box out...we shall see. 
I do have a bently, ill dig that out too.

[VTPSD]

found the issue, the gear/lever that actuates the door in question was broken. Anyone have one of these laying around they want to sell?
 

[williamtaygan]

Lucky lucky! I've got one for you.  I'm parting out my 91 Jetta Ecodiesel this week.

Will in Alaska

found the issue, the gear/lever that actuates the door in question was broken. Anyone have one of these laying around they want to sell?