Question for RHD (closest to driver window) air vent scheme?, A new discovery! for me at least... Options

[UTSlickVic]

Well as some may know I just installed a UK spec OEM "rear" fog button (but Im using it for my fwd fogs (see link if interested).

Anywho I was putting the cherry on top of my little project by repainting the white "flow on/off" symbols on the bottom of the controls. My plan was to make a stensel of the original symbols so the come out perfect. Since mine were very faded I used the RHD (closest to driver window) vent for the blue when I noticed it had an extra symbol than the USDM.



I was like ummm why?... the mechanism looks sort of the same... After closer inspection. I found this (USDM on right, UKDM on left) Pic below shows top veiw looking down.


Both vents diverge making two ducts, an upper and lower duct. Both US and UK vents share the same lower duct. However, the USDM upper duct is a false duct. I always wondered why that was designed that way. The picture above shows you a top view looking down-into the upper ducts. Well as you can see the UKDM upper duct is not a false duct like the USDM, it has an extra extra mechanism to open the upper duct, hence the extra setting. the extra setting opens the upper duct (while keeping the lower open) and its sybolized as bringing air from the outside in. Muck like our center console button.

Long story short, I can replace my US duct section with the UK, because everything is basically setup the same... its just the UK setup has an extra door and extra gears... but it will work , take my word for it.

See pic below. Looking at the bottoms of vents. UK right, US left.


My question is:
If I install my vento have the extra door/setting, where is the upper duct getting the air? it look like it should connect to something, but I dint remember anything to connect to the upper duct. are the vent shemes that differcent between the overseas and USDM?

if the pics are too dark let me know... I thought it was just my monitor.

[vsideboy]

my jap import has the additional venting. There are 2 tubes behind the dash that this vent clips into, one is venting air from outside the car (not sure where from exactly without further inspection, but most probably the same place the air comes into the haeter unit) and the other comes from the heater unit.