1971 Chevy Corvette Windshield Wipers

I have replaced the on off switch on the wipers and still does not work. I have wired the motor direct and wiper motor does come on. The wiper door will open when car is running and wipers are turned on but wipers will not work, I have been told there is a limit switch that tells the motor that the door is open and it is ok for wipers to come on. Is this true and if so where is it located?

Thanks
Bobby