12V Electric Wiper Conversion - 1954 Pontiac
I picked up a wiper motor off of my 76 Camaro parts car and mounted it on the firewall. A little testing and comparison to the wiring diagrams and its operation was figured out. From what I can figure out here's the operation:
Figuring out the wiring and testing
Yellow wire +12V supply Ground the following wires: Blue wire Hi speed Black / Blue wires Low speed Black and blue open Off
Note: The wiper motor is grounded to the firewall through one of the mounting screws. If there is a bad connection, the wipers will not return to the rest position.
Here's the order :
- Single wire connector: Black
- Double wire connector:
- Wire closest to single wire connector (middle wire): Blue
- Remaining wire: Black/Yellow or Yellow
Wiper Motor Switch
Well the wiper switch is not as easy to wire as first thought. I went to the wreckers and picked up a nice wiper motor switch from a Chrysler pickup and found out it didn't work:
Chrysler pickup wiper switch
Chrysler pickup wiper switch pins
Chrysler pickup wiper switch schematic
P1 - B always connected Rotary Positions: Position 3: H - P1 Position 2: A - P1 Position 1: A - P2 Washer Pushbutton: B - W
When I connected up the Chrysler switch to the GM wiper motor, it almost worked. After a few attempts and a futile attempt at adding a diode to fool it, the best that it would do is off, low speed and high speed then it would not turn off even if you disconnected the switch! The GM wiper motor needs the following switch and it's got a slightly different schematic
The Right Stuff - GM Wiper/Washer Switch
I picked up a wiper/washer switch off of a 1968 Chevy van. which had the rotary style switch I was looking for. Pretty much any 60s GM vehicle will have a rotary style 2 speed wiper/washer motor switch that will work. I was hoping to find one with a chrome knob but wasn't so lucky. Later GM models use a slide style of switch which wouldn't fit with my 54 Pontiac dash.
GM wiper switch
GM wiper switch pins
GM wiper switch schematic
Case is connected to ground Rotary Positions: Position 3: Gnd to Hi speed Position 2: Gnd to Hi speed Gnd to Lo speed Position 1: Hi Speed to Lo speed Washer Pushbutton: Gnd - Washer
The interesting thing about the GM wiper motor operation is that both Lo and Hi speed have to be connected to ground for low speed operation. And to turn it off, the Hi speed is connected to Lo speed but NOT grounded. There is a switch inside the wiper motor that grounds the off position putting it into Lo speed until the wiper arms return to the rest position. The result is the wipers still move after they are turned off until they return to the rest position.