1989 Ford Taurus Trying to rebuild turn signal

Electrical problem
1989 Ford Taurus 6 cyl Front Wheel Drive Automatic

We've been having an ongoing problem with the turn signal in this car, and I've pretty much given up on it. When I use the turn signal, a signal is going to the brake light system showing that a turn signal is in use, so the brake light won't turn on, however, the turn signal does not turn on. It was thought that the problem was in the switch arm for the turn signal, and that whole unit was replaced with an almost new one (pulled from a junkyard, but car was only a year old when it was totaled). It worked for awhile, but the turn signal went out again. What I'm looking at doing is to build a custom turn signal using a two way rocker switch that i'll mount on the car somewhere in easy reach. It would let me turn the turn signals on manually, although turning the wheel back would no longer turn the signal off, i'd have to turn it off myself.

To do this, though, I need a wiring diagram of at least the rocker arm if not the whole turn signal system, as I would like preferably for the dash lights and hazard switch to still work (but I could build my new turn signal to work those functions as well)

Any help will be greatly appreciated.