Airduct Question

[SkyMac]

Hi
Need some help with my 74G model, whilst all the instruments are out I am replacing all the ducting, vacuum hoses etc. My need for assistance is on the ducting pipe connected to air intake scoop just above the static point of the right hand side.

This particular duct goes to where? in my airplane it ends behind what would have been the old avionics stack (which was hastily removed by the previous owner), it has a "Y" junction at this point, no more hose or fittings. I have a number of thoughts on it's use, but would appreciate some guidance.

I am able to locate the vent intake, but the actual duct itself, where or what it feeds air to or attaches to in the parts manual I cannot find.

Thanks everyone