Two-Speed Windshield
Wiper/Washer System

I have looked high and low and have never been able to find a wiring diagram for the two-speed washer/wiper system used in 60s GM cars and trucks. The following is shared with us by Vaughn Whitney who obtained the information from an unknown source who traced each wire in the system on a '65 Corvair Greenbrier. The wire colors indicated in the sketch are from the Greenbrier and I'm not certain that the colors will be the same in other vehicle with the same system.

Operation: When the ignition is on, +12 volts is continually provided to the washer/wiper assembly through wires C and D. When the switch is turned to the SLOW position, the wiper motor is grounded through both wires B-H and A-F; the wiper will begin to operate slowly. When the switch is advanced to the HIGH-SPEED position, the wiper motor is grounded through wire B-H only; the wipers will then speed up. When the washer button is pushed, the wiper is grounded through wire B-H and the washer pump is grounded through wire E-G.

 
If a modern continuous-flow electric washer fluid pump is preferred instead of the stock unit, connect wire D-J to one of the pump connectors and wire E-G to the other. Verify proper fluid flow direction. If the pump is running backwards just reverse the leads. The pump will shoot fluid through the nozzles as long as the washer button is depressed.