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.

Had the same probelm. Took out the board, re heated the connections, and not a problem since.