Stopping wipers

Going from memory, 20 or more years ago;
There is a sorta complicated parking switch in there, and a resistor block screwed onto the outside. My first guess is that the resistor is balky, when hot. and second guess is the parking sw.
That is a DC motor, so it has brushes, and it has brass bushings like the heater blower motor. So after so many decades, it might require servicing.