Wipers only run on high. Bad switch or bad motor?

[David B]

I just purchased a 1970 Barracuda. The wiper motor only runs on high speed or off. It does not work in the slow speed nor will it park. Is this an indication that I need a rebuilt switch, overhauled wiper motor, or that it has been wired incorrectly? Anyone have a recommendation on where to start troubleshooting?

 

[dongei]

Mine won't park either. I think it's in the motor on mine.

 

[moparleo]

Welcome to the site. Is it a 2 speed motor or a 3 speed motor?

 

[Adam]

The service manual has a section for trouble shooting the wipers specifically for things such as not parking.. it's probably not the motor, but dirty contacts.

 

[burntorange70]

Welcome to the site.

 

[David B]

I guess I posted the question to the wrong site. But here are pics of the motor & switch.

 

[msclecarlvr]

My brothers Duster had a similar issue. Turned out to be a bad ground.

 

[dongei]

I have a '70 Challenger and my motor is nothing like yours. What is up with that? Mine is a 2 speed I think, (I have never drove it in the rain) and only works on 2 speeds.

 

[js29]

I have a '70 Challenger and my motor is nothing like yours. What is up with that? Mine is a 2 speed I think, (I have never drove it in the rain) and only works on 2 speeds.

You would have A 2-speed wiper motor, the one in the picture is what is known as A3-speed. it is actually A variable speed set up.

 

[dongei]

Dooooh !

 

[resq302]

Found from a post over on cuda-challenger.com

Testing a 3-speed wiper system

The 3 speed wiper system controls the speed by use of a resister in the switch, not in the motor. The switch also reverses the current to the motor in the "off" position, which causes the motor to seek the "home" position. There is also a circuit breaker built into the switch to protect the circuitry.

Testing the switch

There is a test for the switch that can be done with a continuity tester or an ohmeter. To do this test, on the back of the switch, the terminals are marked with an"A", "B", "B/U", "F1", "F2", "P" and "R1". In the tests, "Ground" is the switch casing.
While in the "Off" position there should be continuity between
B to B/U
B/U to P
A to F2
F1 to Ground

"LOW"
B to B/U
B/U to A
A to F1
F2 to ground
P - open

"Medium"
B to B/U
B/U to A
A to R1
F2 to ground
P - open

"HIGH"
B to B/U
B/U to A
F2 to ground
P - open

Testing the motor

The motor only has two speeds, high and low. The medium speed is a variable speed, which is configured by the switch varying the voltage to the motor.

"Low"
Connect the motor housing and the green wire to ground
Bridge the brown and red wires
Connect either the brown or red wires to 12v
Motor should turn slowly

"High"
Conect the motor housing and the green wire to ground
Connect the brown wire to 12v
Motor should turn fast

"Park"
Connect the motor housing and the red wire to ground
Bridge the brown and green wires
Connect the blue wire to 12v
Motor should turn backward, then stop in park position.

Rick Kreuziger