Variable speed vs. 3 speed wipers
I believe variable up to and including 1971. 3 speed began in 1972.
They use the same motor, the controls are in the switch. 1n 1972, you can see the big resister on the side of the switch. The variable are larger and have a sweeping motion with the switch knob. The wiring harness plugs are also different. My 1971 has a 2 piece plug that gets oriented based on a 2 spd vs 3 spd option. In '72 it is one plug.
I hypothesize.........You could run 3 speed wipers in the earlier models if you can't find a variable switch. I believe that would entail removing the individual wires from the early plug, and inserting them in the correct locations of the newer plug. Never tested it though! :)
NOTE.....3 speed/variable motors are different than 2 speed motors.
.......3 Speed.
........Variable Speed.
I believe variable up to and including 1971. 3 speed began in 1972.
They use the same motor, the controls are in the switch. 1n 1972, you can see the big resister on the side of the switch. The variable are larger and have a sweeping motion with the switch knob. The wiring harness plugs are also different. My 1971 has a 2 piece plug that gets oriented based on a 2 spd vs 3 spd option. In '72 it is one plug.
I hypothesize.........You could run 3 speed wipers in the earlier models if you can't find a variable switch. I believe that would entail removing the individual wires from the early plug, and inserting them in the correct locations of the newer plug. Never tested it though! :)
NOTE.....3 speed/variable motors are different than 2 speed motors.