When I got my car (92 Bird, 3.1L) the coolant lines to the heater core were disconnected and plugged. Now that its colder than a witch's t**ty outside, I really would like my heater back on :-P I looked under the hood today before my trip to work, and I only see one connection point for the core. Tracing the lines back from the fire wall, I see they both go into a black plastic thing with a vacuum port on top (which I assume to be a heater control valve). One of the lines has a t-connector in the metal portion that is open. Obviously I connect one line here, but were does the other line go?!?!?!!? I know I'm missing something really obvious, but I stared at that side of the engine for a good 15 minutes, and couldn't figure out where the lines went.

 

water pump

 

Alright, -I have one line coming from the junction block on the front of
the engine, and this is where the TB lines also connect. I also have a line
coming from the water pump. Both of these lines are capped off (well,
actually plugged with a lugnut on one, and a condensor on the other, lol)
near the control valve. Hopefully the pics that can be found at:
http://f1.pg.photos.yahoo.com/ph/jee...src=ph&.view=t
&start=1&.rand=10132647790 can help explain this a little better. The line
from the water pump (the one in the picture wrapped in duct tape) looks to
connect to the metal pipe that it is sitting near. This metal pipe is a T
fitting, with the upper end going to the upper port on the control valve.
The lower end of the pipe connects to the driver's side port on the
firewall. The passenger side port on the firewall connects to the lower
port on the control valve. This leaves the line from the TB area
unaccounted for. I also only have the one opening into the heater core
circuit, as far as I can tell. The only thing that I can think of is that
the lines from the heater core are incorrectly plumbed to the control valve?