I recently installed an aftermarket radio in my 88 Dodge D100. Afterwards the vent control no longer worked. Everything comes out of the center vents. It does not matter if I select defrost, vent, heat (floor), etc, everything comes out of the center vents.
After doing a bit of Google searching and consulting my trusty Haynes manual I see that everything is controlled by vacuum. A little more digging and I saw that while installing the radio, I must have disconnected the vacuum lines that go between the actuators for the various dampers and the controller in the dash.
There are 6 black vacuum lines and one red vacuum line coming out of the controller. All of the black lines tie into a plastic manifold. The red vacuum line is on its own. The manifold has two rows of ports. One row has three ports and the other row has four ports. Not all of the ports on the manifold are used.
I put some pictures of the manifold on my little webserver. You can see them at http://andyandchrissy.webhop.net/dodge.html
The lines coming from the actuators are color coded: green, yellow, red, brown, grey and black. The black line is coming from the engine, the grey is to close a valve that shuts off water flow through the heater core, the yellow controls the floor (heat) vent actuator, the green controls the recirc/fresh air actuator, the red controls the defrost vent actuator, and the brown controls the actuator for the dash vents.
The problem is that I have no idea how these vents should hook up to the controller and there is not a diagram or reference to them in the Haynes manual.
Also, I have not had much luck with trying to figure everything out by randomly plugging vacuum lines into the manifold.
I was hoping someone has a factory service manual or some personal knowledge and could help me out in re-attaching all the lines to the manifold in the correct order.
Thanks in advance for any help!