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MG Midget and Sprite Technical - Wiper wiring

Hi trying to put my wiper system back together , thanks for all the previous advice. I am now trying to wire up the single sped wiper and getting it to park.
I have a Lucas on/off switch number 34426E I am not sure if it's the right switch and can't get it to make the wipers park .
The motor is earthed , I have supplied a live feed from the ignition via the green wire and when I apply 12v to the red/ green wire the wipers run . Now what should happen with the brown/ green wire, should I get an intermittent voltage or does it earth to park ? Loads on google and archive but struggling , already melted 1 test lead !
Mike Fairclough

The wiring and components will be the same as on an early MGB so have a look at Paul Hunt's description with diagrams of how it works. The link is:
http://www.mgb-stuff.org.uk/electricstext2.htm#wipers
Mike Howlett

There were a number of different systems used on the MGB, so probably not the best example to use.

A lot of non-parking problems are down to using the incorrect switch.

IIRC your car originally had a square motor but now has a round one. The parking circuits for these two motors are different, as are the switches, I believe.
Dave O'Neill 2

Thanks Mike and Dave I have put the wiper motor from my 1970 car on it and the switch was with it but I can't remember if it ever parked on that car either . When the motor runs I seem to be getting a brief earth from the brown / green (park) wire with each revolution but I can't see how attaching that to the switch will make a circuit
Mike Fairclough

Mike,
IIRC you have a toggle switch and two speed square body motor.

Have you checked on the rotor gear (& arm) that the park ramp isn't missing?

For wiring have a good read of below (it might mean you need the Holden switch which it links to?). Read down to the paragraph that starts "To update single-speed systems to two-speed ..." and note that paragraph -
http://www.mgb-stuff.org.uk/wiper3.htm#3

link to switch (included in above) -
http://www.holden.co.uk/displayproduct.asp?sg=1&pgCode=020&sgName=Electrical&pgName=Switches&agCode=0502&agName=Toggle+Switches&pCode=35927

wiring diagram of that switch
http://www.holden.co.uk/productImagesWD/35927.jpg

Reference sheet, page 1, that shows 34426 and 35927 are 57SA -
http://www.northwestclassic.co.uk/LUCAS%20SWITCHES.%20RELAYS.FLASHER%20UNITS%20&%20WIPER%20MOTORS%20&%20PARTS.pdf

N Atkins

ETA: links fell out! bl**dy computers!!

Try:
Lucas 57SA Type Off-on-on Toggle Switch for Wipers -
http://www.holden.co.uk/displayproduct.asp?pCode=35927
N Atkins

Mike,
you ignore the E on the end of your switch part number.

From Holden's site -
"If you have a Lucas part on your vehicle and are seeking a new replacement, the key to identifying what you is the Lucas part number. Taking a switch as an example, it was have a five/six/eight digit number stamped or moulded into the part (often this is very small). It may be followed by a letter A/B/C etc but these can be ignored."

http://www.holden.co.uk/displayProductsByBrand.asp?brand=Lucas&brandCode=X8
N Atkins

Amazing how this foxes folk.



Ok, at the motor you need a 12v supply (green), an earth (black), 1st speed feed (light green/red) and the park wire (light green/brown).



When the motor needs to park the park wire supplies a live feed back to the dash switch, test it works by attaching a test lamp to the switch wire and run the motor, it should "pulse" once every revolution.


Once you know the motor park switch functions its just a case of connecting the switch up correctly! You should have 3 wires, 12v supply (green), motor run (light green/red) and the park (light green/brown). I work it out by trial and error. What you need to achieve is the 12v supply connected to the motor run when switched "on" and connected to the park wire when "off".

The switch has a connection in it that does this.


So if connected right the limit switch supplies the motor run wire via the switch until the park switch opens and shorts the motor to ground and it stops dead.


If it parks the wrong side the ramp inside the motor needs unclipping and moving to the opposite side.


Hope that is clear.
Steve Smith

Steve,
excellent stuff.

With Mike's situation there's been a possible mix of switch(es?), mix of motor and wires/connecting plug, plus the following from Paul's site (which may or may not be relevant in Mike's case) - "Also note that the two-speed switches Bruce Cunha got from both Moss US and Victoria British are not suitable as they do not offer the park function required by the two-speed motor.".
N Atkins

Maybe Mr A,

But the round bodied, 1e 14W type motors all use a moulded 5 pin plug, the only differences are between single and dual speed.



The old DR3 square bodied motors work on a totally different principle and the wiring is not the same, as the paring is all done within the motor.


The 2 speed versions of that have lots of wires and a complex switch, don't think any MG ever used a 2 speed square bodied type tbh.
Steve Smith

Blimey thanks for all the replies to this , I have looked at most of the Holden stuff but not all. Just to confirm I have now put on a single speed round wiper from my old 1970 car . Before I get to connecting the switch I have been trying to simulate it with test wires etc . Steve your description is kind of what I expected it to do but I don't seem to be getting a pulse live from the Park wire so I assume the supply from the green is not getting through somehow , so could be a fault with the oark switch do you think ? I do get as I said some sort of earth through the park wire at each revolution , this could be the grounding to stop it dead that you mentioned maybe ?
Mike Fairclough

Mike,
IIRC the later/more modern round body motor is 2 speed so if you have the right switch it will be 2 speed, IIRC you were saying you were going back to single speed, at that time I thought this was because you had a single speed switch.

You put you got the switch and motor from your 1970 car (and the motor was swapped from square?) but not which model/year car you were putting these in now - (view able) vehicle profiles help with these sort of things.
N Atkins

Hi Steve,
my train of thought was that there was a period where Lucas (marked/boxed) electrical parts were poorly made and with that note about two different suppliers selling switches that didn't work the way that was required for the wipers that Mike might have such a switch now.

Of course it's only a possibility.
N Atkins

Thanks Nigel I am afraid the car is a whole mixture of bits that doesn't help it's a 1966 car that was raced so lots of stuff has been taken out and put back in from a range of years , hence why I decided to put all my wiper system in from my 1970 car that I broke a few years back . It is negative earth as well . The round body wiper I have is only single speed as standard , not sure any midgets had two speed , maybe American or late 1500's
Mike Fairclough

Hi Mike,

It does sound like your park switch is faulty unfortunately.


They can be bought separately, 2 types.............one clips in, easy to swop. The other has 2 screws which are under the drive wheel, more difficult to swap.

And not all 14W motors are 2 speed. If there are 5 pins in the plug and 3 wires going into the motor body it is,the single speed only has 2 wires.
Steve Smith

Sorry, Mike I missed the fact you'd put you'd got a single speed motor, I was doing two things (badly) at once, I was thinking if you had a 2 speed motor and 2 speed switch you could wire it to get both.

Of course I can't find it now but I thought I read something about park being with the slow speed as regards the switch(?) operation - but I can't check now as my distraction needs attention.

The info you put about your car would be ideal on your vehicle profile.

ETA: typed as Steve posted.

I can tell you how not to put the park ramp/gear wheel position back into the motor (wipers go on to bonnet).
N Atkins

Thanks everyone , tomorrow I will mostly be playing with park switches
Mike Fairclough

This thread was discussed between 16/03/2017 and 17/03/2017

MG Midget and Sprite Technical index

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