Page 1 of 1

2 speed wiper motor woes

PostPosted: Tue Jan 14, 2020 9:31 pm
by s28ven
So I think I?ve eventually figured out the wiring on the motor.

I have three wires from the motor plus earth from the casing, red, green and yellow.

Green goes to ignition live, earth to chassis and the two switch wires to earth for slow and one to earth for fast.

Can anyone tell me which single switch wire should contact earth for fast?

During bench test I can only get the motor to run on fast and return to park not on slow.

Can anyone tell me why?

The resistance between the wires are as follows Yellow to green 8.7 yellow to red 10.3 green to red 2.0.

Thanks,
Steven

Re: 2 speed wiper motor woes

PostPosted: Tue Jan 14, 2020 10:00 pm
by pharriso
See attached:
WiperSwitchMotor_logic.pdf
(418.07 KiB) Downloaded 103 times

Re: 2 speed wiper motor woes

PostPosted: Tue Jan 14, 2020 10:34 pm
by s28ven
Thanks for the reply although from what I have read this doesn?t seem to be correct.

The motor is a lucas square DR3A and from what I understand this motor is switched through the earth. Both switch wires to earth gives the slow speed, one switch wire to earth give the fast speed and no switch wires to earth returns to motor to park.

Thanks, Steven

Re: 2 speed wiper motor woes

PostPosted: Tue Jan 14, 2020 11:29 pm
by Craven
If you have a square body motor, DR3a, it is basically a single speed wiper motor.
fast speed is achieved by placing a resistor in series with the field winding.
See web or this diagram may explain.
DR3a.jpg
DR3a.jpg (17.28 KiB) Viewed 769 times

https://www.thorden.dk/Teknik/two-speed.pdf

Re: 2 speed wiper motor woes

PostPosted: Tue Jan 14, 2020 11:43 pm
by pharriso
s28ven wrote:Thanks for the reply although from what I have read this doesn?t seem to be correct.

The motor is a lucas square DR3A....

Thanks, Steven


Always useful to mention what series and/or year car you are talking about as the car's did develop over time.

My wiring diagram is for a S4 or Sprint....

Re: 2 speed wiper motor woes

PostPosted: Thu Jan 16, 2020 10:35 pm
by s28ven
Thanks for you replies and sorry for not providing they type of motor in the first post.

I have studied the correct wiring diagram and as much as I understand the basics, the reason the motor will only run on fast or slow when parking has me stumped.

Is it running slow when parking due to a poor earth and simply causing my confusion?

Any help would be greatly appreciated as I don?t really want to pay a lot of money to get it refurbished when it could be a simple fix!

Does anyone have a picture of how the brushes should look?

Thanks, Steven

Re: 2 speed wiper motor woes

PostPosted: Thu Jan 16, 2020 11:19 pm
by Craven
From the Text in the link I posted, https://www.thorden.dk/Teknik/two-speed.pdf

Notice that the self-parker will operate in the same way as the fast-switch. So the motor will park at high-speed!

When the control switch is in the OFF position, no speed is selected.

Re: 2 speed wiper motor woes

PostPosted: Fri Jan 17, 2020 9:51 pm
by s28ven
I have managed to find a very knowledgable and helpful gent on another site and it turns out the motor I have is a constant variable motor which should be controlled by a rheostat switch. Looks like I need to wire in a resistor in order to use as a fixed 2 speed.

Thanks for all your replies.

Steven