I had been sort of wondering for some time what to do about redirecting the airflow from the vent located in the middle of the stock OEM dash. I figured since I had that cover plate I had made out of Lexan plastic to help separate and protect the backs of the Knight Rider dash circuit boards from coming into contact with a bunch of loose flying wires I would see about somehow giving it another job as well, like attaching some sort of vent to allow the air to from through that vent opening in the OEM dash and more out from under the dash.
So what I came up with was to first make a rectangular box made from some high density foam rubber I picked up from a Craft store (Micheal's). I used black Gorilla Tape to hold the shape of the foam box together and then inserted it into the OEM dash vent opening. (above left). It's a snug fit and friction alone seems to keep it securely in place although I could glue it in with some contact cement if I find I need too. This box brings the vent opening up close to the back over my Lexan plastic cover plate.
I then cut out a square shaped hole in the Lexan plastic cover plate over the area of where the air vent matches up with the plate. I was looking for some sort of pre-made vent covering that I could use on the front part of my cover plate to redirect the air flow downwards but was not having a lot of luck, I did manage to find a small plastic tray from Dollarama for a buck that I could cut off one side that would pretty much do the trick (above right). I secured that to the front of my cover plate with 3 small bolts and some washers (left).
I'm not yet ready to secure the cover plate into place yet as I am still doing a fair bit of electrical wiring work in that area of the dash but when I am finished the cover plate will be secured into place and should serve the double purpose of protecting my wires from coming into contact with the back of my Knight Rider dash circuit boards and provide a nice opening to allow the airflow from the middle vent to flow downwards out under the dash.