Wiper motor

[Roy '65]

Well, finally got the A/C installed yesterday and today started to get the wipers wired. No problem as the hot wire from the switch went to the top terminal on the motor and the bottom terminal went to ground. Motor runs fine ...........in one direction only so when hooked up to the wipers only will run one way and not come back. My question is this a defective motor, wrong motor or do I have it hooked up wrong? The motor came with the car when I bought it and was supposed to be new and never hooked up until today.