2 speed wiper motor questions

[str12-340]

1970 Dodge Dart. Attached to my 2 speed wiper motor is what looks like a ceramic ballast resistor. Does someone know the function of this thing? My 3 and variable speed motors never had anything like this. I don't see this at all in the FSM service manual wiring diagram.

There seem to be lots of options as far as replacing the motor. Is one better then another? Prices seem to range from $50 to $95.

 

[CFD244]

I'm pretty sure that's how it changes speeds. In the 3 and variable speed motors, the speeds are determined by the switch.

 

[Jim Kueneman]

It lowers the current/voltage across the field winding of the motor for low speed.