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Heat only coming from dash vents, no defrost?
by
VTPSD
on 14 May, 2013 05:31
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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.
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#1
by
VTPSD
on 14 May, 2013 05:42
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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...
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#2
by
TylerDurden
on 14 May, 2013 07:54
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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.
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#3
by
VTPSD
on 14 May, 2013 07:56
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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.
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#4
by
TylerDurden
on 14 May, 2013 08:01
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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.
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#5
by
VTPSD
on 14 May, 2013 08:04
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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.
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#6
by
williamtaygan
on 14 May, 2013 08:11
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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.
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#7
by
CRSMP5
on 14 May, 2013 08:34
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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
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#8
by
VTPSD
on 14 May, 2013 08:44
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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.
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#9
by
VTPSD
on 14 May, 2013 18:04
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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?
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#10
by
williamtaygan
on 14 May, 2013 18:23
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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?
