67 2 Speed Wiper Switch Demystified

[Dana67Dart]

Some time back I was disassembling and cleaning the switches from my 67 Dart Convertible #2. All went well till I got to the wiper switch.

Switch number 2820525, 2 speed with the resister on the back

I successfully got the switch open without breaking anything, always a good thing, which was surprising as the pot metal usually breaks where it is crimped. Then I saw the killer broken part (very sad, only thing wrong with the switch)

There is supposed to be a round plastic disk there!

The disk insulates the push button feature of the switch to power the washer pump. Without it the push button shorts out the contact making a short to ground.

Edit: Light bulb time... make a piece! So I 3D printed a replacement part. Not sure how long it will last, but it fits great and is made of some tough material.

As you can see I have a few extra so PM me if you want to test out one on your switch.

But I have gotten ahead of my self...

Once the switch is opened you can see the contact on the inside of the back. There is an insulating board where you can see the mating contacts ride up on in certain switch positions.

The switch consists of 6 main parts
from left to right

The housing
The knob shaft
A double pole contact holders
A single pole contact holder
The insulating board
The back with the contacts and terminals

Nothing exciting about the housing... it has 3 detents for the single pole contact holder and 2 for the 2 pole contact holder

The shaft also not very exciting, a snap ring, a flat for the single pole contact holder and a rounded post on the end to depress the washer contact

Here is where things get interesting...

The double contact holder has gear teeth on the side and a hole in the bottom to sit on a post on the housing. These teeth engage with the single contact holders gear teeth.

The back has some interesting features as well.


#1 is the built in circuit breaker.
#2 is the momentary contact that the stem presses on.

The terminal side is also interesting.

#1 is a terminal that feed power to another device. rather than them running an additional wire that tapped off this switch, go figure!
#2 is the resister that reduces the current flow to slow the wiper motor down.

 

[Dana67Dart]

More interesting stuff.

The shaft rotates the single contact holder

Off position (fully CCW)

Low speed position (one detent CW)

Hi speed position (2 detents CW)

Same but with insulator in place

 

[Dana67Dart]

Now with the 2 pole contact holder installed

With insulating cover on.

Note that the 2 pole contact holder did not move from detent 2 to detent 3. The gears purposefully cause this.

 

[Dana67Dart]

Turns out the FSM already did most of it for me!
The resister is in the 26 ohms

And guess who is 3D printing the broken plastic button?

 

[Dana67Dart]

Place holder

 

[Dana67Dart]

Place holder

 

[Syleng1]

Very cool stuff right there. Imagine the person who designed that switch. All because a 3 way toggle switch was not good enough. So much complexity and size to accommodate the heat. Thanks for sharing.

 

[Dana67Dart]

On an interesting side note.

One of my motors has only 2 wires going into the actual motor and the other has 3.

In the 1970 master tech video they talk about wiper speed based on which set of windings were used. I'm wondering if that's not the case with the newer style in my 2/67 built dart ( 3 wire) vs my 11/66 built with 2 wires?


2/67 motor 2822963

11/66 motor 2822962 (I believe the white wire was red before 30 years in the sun, the dark wire seems to be brown)

Some good info in this post

2822963 wiper motor 2 speed park bench test

 

[matthon]

I recall when my reverse lights would not come on I would have to turn my wiper switch on and off until the wipers would come on and finally the reverse lights.

I have since powered the reverse lights another way, and now both work without issues.

Strange set up, imo