I found an electric wiper motor for my 56.There are three wires. Black , red , and yellow , I believe.Touching which ones to a battery should make it run? I assume black is ground and the other two would be low and high speed. Correct?

 

I'd say you're correct. I'd tell you for sure but my truck's wiring is gutted at the moment, as I'm rewiring it. Might be able to hit it with an ohm meter to make sure that black wire is in fact a ground.

 

I think the black is power from ign, on replacement switch and ground on original. Study the switch wire hookup in the shop manual or Mid Fifties instructions on their web site.

 

I beleive red is hi, yellow is low and black is park not ground. The motor grounds itself. The three go to the switch and then a power wire comes from the fuse to the switch. Mid Fifties should have a diagram. I know they send one with the motor kits.
To see if the motor works, hold the motor against the neg post of a battery, touch the black on the positive post and it should just move to park, touch the yellow and it should have low, touch the yellow and red and that should be hi.

 

I agree that some combination like the previous post .
Park position settings since the very early days.

 

Ah! I stand corrected! Forgot to consider the park function...duh.

 

Hi,
I don't know if this will help or confuse the issue. My manual shows a red, black and a GREEN wire coming from the motor to the switch. All three wires going to the switch. Red to terminal "A", black to terminal "P" and green to terminal "F". Terminal "B" on the switch has a yellow wire going to Acc. terminal on the ignition switch.
If you have a wiper switch why not wire the motor to it to see if it works? I know I would probably just take a chance and guess at it but if you want to do it the safe way.

 

Hope this helps...

 

If your "new truck" wiper motor still works like the '51 wiper motor, all 3 wires on the motor are "hot" at one time or another, depending on the position of the switch. The body of the motor is grounded to the frame through the mounting bracket. One lead is for High speed, one for Low speed, and one for Park. When the park switch is made, there is no difference in potential across the motor windings (6 volts on both sides of the motor in my case, which equals 0vdc), so it coasts to a stop.

To test the motor, hook a battery charger lead to the motor frame, and the other lead to any of the 3 connectors on the motor.

Mine is 6 volts, and was "stuck" until I hit it with 12 volts. I also had to remove the 60 year old grease, and replace it with good grease. Hope this helps.

 

Just went out and checked my '56 wiper motor.

On the motor-
Black = park
Red only = high speed
Red + Green = low speed.

On the back of switch, key on-
Off (park) = Black wire hot only
Low speed = Black+Red+Green all hot
Hi speed = Black+Red hot

 

When I attach the red and green wires together the motor is running in slow speed correctly, but when I attach only the red wire to switch to high speed the resistor is running hot and almost starts burning. I have 2 motors and they both react the same. Can you help me out?

Paul.

 

Note- This Thread is 7+ years old. Info will still be good if any is given. Good luck.