Testing a windshield wiper motor?

Hey guys, I just picked up a 72 Cuda. Nice car, but the wipers are not working. I pulled the switch and I have voltage at the switch. I pulled the wiper motor plug from the firewall and tested there, I have voltage there. Could be a bad ground or a bad motor. I want to run a jumper wire direct to the wiper motor (3 speed). Which wire should I run the jumper to (or does it matter) and which wire on the motor is the ground?

Laine.

FSM has the procedure. Check the attachment in the third post in this thread:

https://board.moparts.org/ubbthreads/showflat.php?Number=5603884

Turn the wipers on and LIGHTLY tap the motor.

If its starts spinning you need replacement or rebuild your motor.