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> Bench testing 1973 Intermittent Wiper, Confusion around wiper behavior
GeorgeKopf
post Jun 15 2025, 11:48 AM
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I'm bench testing my wiper motor without the intermittent wiper relay in the circuit.

1. Connect ground.
2. Apply power to red/white or red/black (53a)
(wipers park at the down position)
3. Apply power to black/blue (53)
(wipers run at the slow speed; when black/blue is disconnected the wipers park)
4. Apply power to black/purple (53b)
(wipers run at fast speed; when black/purple is disconnected the wipers park)
5. Apply power to green/white (31b)
(nothing happens)

Shouldn't this initiate one cycle of the wiper arms, after which they should park?
My understanding is that the wiper relay sends a periodic pulse through the green/white wire to trigger one cycle (one wipe).

If I apply power to red/white(53a), black/blue(53) and green/white(31b) and then remove the black/blue(53), leaving power to red/white(53a) and green/white(31b), the motor continues to run with a tiny pause where it would normally park. It seems that once it gets started the green/white(31b) prevents it from parking. If I remove power to the green/white(31b), the motor parks and cannot be restarted with just power to green/white(31b).

With the intermittent relay connected, the behavior is exactly the same, BUT I hear the relay chirp in between each cycle.

I'm hoping that my wiper motor is working correctly and that my relay is bad.

Am I testing this wrong?



Thanks.

George
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ClayPerrine
post Jun 16 2025, 06:51 AM
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Red/White is switched power from the ignition switch via the fuse box. For testing it should have power all the time

Green/White comes from the wiper switch. It is energized when the wiper switch is in the on position, low or high. It keeps the wipers running all the time once started.

Black/Blue is the start signal to the wipers. It comes on to make the wipers start moving. If power is applied to the Black/Blue wire and removed, and the Green/White wire is powered on, then the wipers will keep going. If power is applied to the Black/Blue wire and the Green/White is not powered on, then the wipers will make one pass and park again.

I don't have a diagram for the intermittent wiper relay. The only wire shown on the wiring diagram for it is Brown/Black, but it shows no connection at the motor. I do know that one of the wires from the intermittent wiper relay will supply a pulse of power when the relay energizes. Connect that to the same terminal as the Black/Blue wire and your intermittent wipers should work correctly.
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ClayPerrine
post Jun 16 2025, 06:59 AM
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Did some checking online. Here are the connection directions.


C) Locate the 4 wires on the wiper motor (Fig. 8)
The wiper motor wires are color coded as follows: red/black, green/white, black/blue,
black/purple
D) Insert the relay harness wires in line with the original motor wires (Figs. 7, 9)
1) Remove the red/black wire from the wiper motor. Attach the relay red wire to the
motor (it has a double connector) then put the red/black back on the second pin.
2) Remove the green/white wire from the motor and attach it to the relay blue/black wire
(male connector, inside the box housing)
3) Take the relay green/white wire and attach it to the previous original green/white
connector on the wiper motor
4) Insert the brown/black wire into the only empty connector in the relay socket
5) Attach the relay brown wire to the wiper motor ground


From https://bowlsby.net/914/WiringHarnesses/doc...nstructions.pdf

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