I own a 91 camaro and the wipers don’t work. they move about an inch and then they make a clicking noise and go back down. I thought the motor was going out so I bought a new one but that didn’t fix the problem. The wiper transmission is fine, it moves just fine if you rotate it manually but I don’t know why it doesn’t work when the motor is running

 

I've had this same problem. If you have intermittent wipers, the problem is likely the circuit board attached to the motor housing. You may be able to find a reproduction at any chain autoparts store, but I bought a used one from Hawk's. Be sure to verify the shape is right since I think they change a bit throughout the years. You may want to such for it as a "pulse board".