Wiper motor testing
It took me a LOT of digging but with a lot of suggestions for locations of info and patching things together, it finally led me to the 72 Plymouth Chassis Manual (page 8-109). This helped me a LOT, hopefully it will help you or others too. It shows not only how the motor is wired but also how the switch is too.
Then using some other diagrams and a wiper harness, if you look straight at the motor, the wires go as follows:
It doesn't seem like it should be this hard to find but it was for me. Thought I'd share it in hopes it may help you or others!!