I'm putting later model defroster boxes in my '70 which didn't seem to be a problem since the only mod appeared to be the added connections for the dash vents supply. But in removing the old ones, I find a small (~1") hose (same cardboard air hose material) running from the top of the passenger side defroster to the top/side of the main fresh air inlet/fan box. It's only on the passenger side, nothing on the drivers side. I don't want to plug this until I know what it's for.
Does anyone know the purpose of this connection?

I think you are talking about the hose that goes to the center air outlet in the dash.
I got the oulet but must have a late defroster box.
Can you change the guts of the new box to the housing of the old / Early box? once you take the thing apart be carefull putting it back together Lots of parts that are orientated only one way and are not aparrent right off.

I wasn't planning to take out or touch the center fresh air inlet/fan box. I would just plug this connection on it once I find out what it is.
Tell me about this "center air outlet". When I first saw this hose I thought it would be to discharge air from the defroster to something in the center of the dash but it looked like it connected at the fresh air inlet area at the center box. I'll go out and take another look.

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I think you are talking about the hose that goes to the center air outlet in the dash.
I got the oulet but must have a late defroster box.
Can you change the guts of the new box to the housing of the old / Early box? once you take the thing apart be carefull putting it back together Lots of parts that are orientated only one way and are not aparrent right off.

Well, that makes me feel stupid. Your right it goes to the "center vent" in the dash. It's covered up by a dash cover which I haven't removed since I bought the car. When I first saw this hose, I thought it was a defroster vent but I just pulled the dash cover back a little bit looking for a defroster outlet right against the windshield which I didn't see. Now that I pull the dash cover back further, I see the center vent which I never noticed on a 914 before.
Since it's source is the defroster outlet, it's purpose must be for supplemental defrosting. When the side vents were added on later models it must have been elimiated since so much more defrost air was being pulled off to go to the dash vents. This means the later models don't have this center dash vent. Does that sound right?

QUOTE (tyler @ Mar 4 2006, 08:01 AM)

Does that sound right?

very much so. late model cars don't have the center vent.

and here's another piece of useless trivia:
the 1970/71/72 194-6 didn't have the center vent either.

Andy