Wiper and Washer Systems: Description and Operation

All P models and 1980---83 Caballero and El Camino models use a compound wound type wiper motor. Motor speeds on this type motor are determined by varying current flow through the motor shunt field. Two different compound wound motors are used depending upon application. A rectangular motor is used on P models and a round motor is used on Caballero and El Camino models.
A permanent magnet type motor is used on all except P models and 1980---83 Caballero and El Camino models. Permanent magnet motors usually have three brushes, common, low and high speed. Motor speeds are determined by completing the circuit to the low or high speed brush, while the common brush is used at both speeds.