Lotus Elan

Variable speed windshield wiper?

PostPost by: msd1107 » Thu Nov 16, 2006 4:52 am

Looking at the wiring diagram, there are two wires going to the windshield wiper motor.

I presume one is the full 12 volts, and one is a lesser voltage that comes from the windshield wiper switch.

Now for the question.

If a variable voltage was presented to the high speed terminal of the windshield moter, would it run the wipers at a variable speed? And is this speed linear with the voltage?

A simple rotary potentiometer on the dash or steering column could accomplish this.

What about this? Has anybody done it? Is it possible?

David
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PostPost by: john.p.clegg » Thu Nov 16, 2006 6:55 am

David
I suppose you could slow them down by putting a variable pot in line,but wouldn't it be rather large to handle the current?

John :wink:
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PostPost by: Frank Howard » Thu Nov 16, 2006 4:34 pm

"...there are two wires going to the windshield wiper motor."

David,

I believe there are 5 wires going to the windshield wiper motor.
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PostPost by: bcmc33 » Thu Nov 16, 2006 6:40 pm

As my 72 Sprint is in pieces, I can confirm that it conforms to the S3/S4 wiring diagrams. Five wires to the motor - four to the switch plus a black wire to ground.

The S1/S2 wiring diagram shows four wires to the motor. One to the fuse box, two to the switch and one to ground.


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PostPost by: msd1107 » Fri Nov 17, 2006 4:58 pm

Sorry guys, I was talking about the two wires carrying +12. It is true, the wiring diagram shows four wires from the wiper switch and five wires to the wiper connector.

I have subsequently gotten a reprint of a Lucas manual. It appears that the wiper motor accepts +12 on two connectors, one of which runs the motor at low speed and the other runs the motor at high speed.

So I would suspect that putting a high current rheostat in series with the high speed connector would give variable speed wipers.

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PostPost by: triumphelan » Sat Nov 18, 2006 6:58 am

I have just added a bias switch which give one wipe ,it is connected to a switched live and then to the brown/green wire going to wiper motor.This saves the wipe switch
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PostPost by: Foxie » Sun Nov 19, 2006 7:34 pm

David,

Whatever the total number of wires going to the wiper motor, depending whether it's single or two speed, there is normally a permanent live, which feeds in all positions except the 'park' position, and a switched live from the wiper switch.

Lowering the operating voltage will slow down and eventually stall the wipers, but it may also burn out the motor.

Hella make a very effective "variwipe " control which will answer all your prayers.

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