[hrc200x]

I can have a pic of the Y defroster duct maybe this weekend, but I'll try to explain better. The large Y shaped air duct that blows on the window... follow the down to where it attaches to the main air duct with all the vaccum lines going to it, it should attach with one bolt in sort of a egged out hole. Where the Y defroster duct meets the main air duct there is probably a inch gap on the firewall side and 1/4 to 1/2 inch gap on the cab side. Even if you could get a tight fit on the cab side, the firewall side seems like it would still have a gap since its mounts at an angle. The 4 screws on the top of the dash that hold the passenger and drive side defroster in kinda determine the angle of where it has to go on the bottom side.

By mechanical do you mean I have to manually flip a lever or somthing? If so, no its all electrical, but I'm guessing none of the plug ins are the same.