Thread: 2 speed wipers

Hello again.

Thanks for the various replies.

Going back to the issue of the switches which is where my main interest lies. My uncertainty over the switch itself lies in having read somewhere - right or wrong - that a normal three position headlight toggle switch (off, live 1, live 2) is not suited for application to two speed windscreen wipers because of the need for self-cancelling.

If wrong (it's all in the motor wiring) then there is no problem. If right then a different switch would be required. I have a new three position windscreen wiper toggle switch from a British spots car - but would prefer to retain a rotary switch if possible albeit two speed with self-parking wipers.

Cheers,

Neil

Originally Posted by S3ute

Hello again.

Thanks for the various replies.

Going back to the issue of the switches which is where my main interest lies. My uncertainty over the switch itself lies in having read somewhere - right or wrong - that a normal three position headlight toggle switch (off, live 1, live 2) is not suited for application to two speed windscreen wipers because of the need for self-cancelling.

If wrong (it's all in the motor wiring) then there is no problem. If right then a different switch would be required. I have a new three position windscreen wiper toggle switch from a British spots car - but would prefer to retain a rotary switch if possible albeit two speed with self-parking wipers.

Cheers,

Neil

why not just temporary wire it to test it out. Then you can tell us

Originally Posted by debruiser

Then you can tell us

I had hoped the flow of expertise might be in the opposite direction.

Might swing by my local auto electrician.

Cheers,

Neil

I don't want to sound precious , but with this self cancelling thing - can't you just turn the switch off when the wipers get back to the rest position? I do this with the rotary switch - it doesn't seem all that difficult. Or is it that the self cancelling action is contained in the motor itself and therefore requires a special switch? I don't understand.
cheers,
D

My take on it is that there are 2 types of wiring concepts in place here and I believe the self park function contained within the wiper motor is independent (in it's operation) to both of them.

1. In an older motor I pulled apart years ago, it looked like there was power supplied (via a suitable fuse) to 2 fields in the wiper motor . The 2 "on" wiper switch positions apply respective earths to each of the fields providing slow and fast functions.

Inside the motor there was a rotary slip ring type contact that maintains an earth (on the low speed field) as long as the wiper arm is away from it's park position.

When the switch is turned off, the self park contact keeps the motor going until the wiper physically reaches it's home position where a break in the slip ring contact removes the earth and the motor stops.

2. With the use of permanent magnet motors I would imagine the concept is similar but the switch is used to control the +ve supply rather than the earth. I have never played with PM motor wipers.

More than happy for someone to clarify my ramblings.

Hello again.

Sitting in Changi Airport with an idle hour or two to fill before heading to India. So, googled "wiring 2 speed wipers" for something to do.

Found a few sites for British sports cars with quite useful 'how to' threads - mainly wiring Lucas 2 speed motors from later model Sprites and MGBs into early Sprites and MGAs. Seems the standard 3 position switch (off, power, power) is fine for the job. The trick is using several relays in an upgraded local harness to get around the self-parking system without burning out the circuit.

Once I manage to digest it all I may be in a better position to share the knowledge.

Cheers,

Neil

by the way , is there a way of identifying a two speed motor from a one speed motor , without taking it to bits?
cheers,
D

G'day All,

POP058 Paul has got it right in his first post. The +12 volts goes to the MOTOR not the switch as such.
Looked at the wiring for the L/R s3 and yes there is +12 volts on the switch however it appears that is for the washer motor.

My mini Clubman has a Lucas self parking 2 speed wiper. The wiring diagram shows the +12 volts goes to the motor only and the switch controls the coils as per Pauls first post. (Maybe an electronic contact cleaner and Lubricator spray may help with the switch).
Don't use WD40 or Inox on switches as it cracks the plastic/nylon components.

Like anything Lucas it's old so requires pulling apart to see what's gone wrong!!!.

Hope this helps.
Chris