The dash switch is always grounded, and so is one side of the motor. To go one way, the switch just applies power to the other motor wire. But to go the other way, it interrupts the constant ground and grounds the other wire, then applies power to the wire which is normally grounded ft.
This might at least get you going in the right direction.
Totally Twisted and Broke makes me a saaaad Panda
"You can almost see the dismay on Phil, Paul & Bob's faces when Trautwig is talking....and the pause in their voices after he stops....after which they pick-up the pieces of his non-sensical commentary and continue with their telling of the story that is the Tour de France! "