Wipers working intermittantly, tap on wiper mototr and motor starts and runs fine, hit a bump and motor turns off. Hit another bump and turns back on?????????
Sounds like the circuit board. These are prone to malfunction. Easily replaced for about $20-$30. It's part of the motor. If you're really diligent, you can take it out and look for the broken or weak connection, probably solder point, and fix it yourself.
