Wiper switch compatability?

It's because inside the motor itself theres a set of park contacts with a plastic ramp or eccentric with a plastic peg. When you flip the dash switch to off, the internal contacts in the dash switch move to the park contacts in the switch. This let's the wiper motor continue to rotate until the plastic ramp , eccentric, or peg separates the contacts in the wiper motor. This turns the motor off. This piece is likely broken. The round cover on the wiper with the wiring soldered to it is where the parking contactor is located.