The wiring diagram for a wiper motor of this car can be found in its maintenance manual. The manual can be purchased at an auto part store.
Classicarwiring.com (eBay)
It's in the Bentley manual for Type 1 1970-1979.
try the local library and get a chiltons repair manual for your car.
Go to the library and get a Chilton's Repair Manual for your year Plymouth.
it looks like a road map
A 1970 Pontiac Service Manual will have this info in it. You can find them on Ebay or one of the literature places on the web.
I restored a 1970 Pontiac Tempest about 15 years ago. I purchased a book that contains very detailed diagrams of every aspect of the car. If you're still looking for a wiring diagram, I can try to dig out this book and find it. (There's no date on this question, so I'm not sure how long ago it was asked)
www.chiltondiy.com and purchase for $19.95 the entire manual, with access for one year.
Scott Wiper was born on July 22, 1970, in Granville, Ohio, USA.
any V8 is 1-8-4-3-6-5-7-2 and the distriburetor rotates counter-clockwise.
Shop manuals are less than $10 on eBay. You'll find all wiring diagrams for mid 1970's - 1982 express NC50 1 and 2. I picked one up on CD and printed it out. Very helpful.
Haynes Repair Manual. In the back on page 12-27. You can then make some copies and color it to help you find your way around.