Lo Operation
WARNING: This page is about a different car, the 2002 Buick Regal and 2002 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.
When the wiper/washer switch is in the LOW position voltage is supplied through a 24K ohm resistor within the switch to the windshield wiper switch signal 2 circuit (Dark Green wire), and accessory voltage is supplied to the windshield wiper switch signal 1 circuit (Gray wire). The reduced voltage from the wiper switch signal 2 circuit (Dark Green wire) and accessory voltage from the wiper switch signal 1 circuit (Gray wire) causes the wiper motor module to close the wiper motor accessory voltage supply circuit (Yellow wire) to the wiper motor low speed terminal.