I'l give it a try. We put a later 3-speed/variable speed wiper motor into a 70 Challenger and it involved switching some wires and it works fine, but I think your motor might have different color wires.
If you have a motor with the plastic park mechanism and two soldered terminals on front, the single (blue, on ours) wire goes from the one-wire terminal closest to the motor "can" to the upper right bulkhead position--the one with the funny shaped corner. The other three wires are coming out of the can and they go as follows:
green- under the blue, bottom right
brown- next to the blue, top left
red- under the brown, next to the green, bottom left
I haven't pulled the later wiper motors apart, but on the '70 style, with the flat (red-wax) style, that single-wire terminal on front goes to a little contact switch that, after the motor has reversed and parks the blades, is pushed open and turns things off, so I'm wondering if that is working properly. By the way, it won't work right if the switch isn't grounded, so if you have things apart on the dash and the switch is just hanging there, clip a little ground wire to it.
Let us know how you're doing with this. Good luck
