Wiper motor removal

Wiper motor removal

Author
Discussion

jensena

5,671 posts

231 months

Tuesday 24th April 2007
quotequote all
adrian@ - Explain please. What do you mean by the design is sited INSIDE the car.

jensena

5,671 posts

231 months

Tuesday 24th April 2007
quotequote all
So you mean on the Mini the motor was sited inside? Even more reason to be annoyed then, cheap old Wiper motor designed to be sited inside, and TVR site it in the engine compartment!
Anyway Adrian you seem to know what you are talking about, so any tips or advice for people like me to cure our wipers which appear to be powered by a 1.5v AA battery!

mars

8,735 posts

215 months

Wednesday 25th April 2007
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Extremely interesting stuff.

So even if we ignore the environmental aspects which are difficult to quantify, the fact that we're all using a higher powered motor is leading to arcing. That in itself probably takes the self park switch outside of its design parameters.

I wonder if there's a way we could isolate the self park switch from the higher currents using a relay... If I had time I'd look into it. In fact, if I hadn't already resolved the problem I reckon it'd be fairly trivial to resolve.

alinton

965 posts

237 months

Wednesday 25th April 2007
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Well, you could. The way it works is this:

The motor assy has three connections: Ignition +ve, Switched +ve from the controller, and ground.

The parking switch is a changeover contact that's operated by a little plastic pin that sits in a detent on a cam. The common of the switch is connected to the motor, the normally open goes to the IGN+ and the Normally closed contact goes to the control+.

When the motor is at rest the parking switch is open. When you switch on the wipers the controller sends a +ve to the motor which then starts to move. As soon as it does, the cam pushes the pin and the parking switch changes over, so that now, the motor is running from IGN+.

So when you switch off the wipers, the control+ is removed and when the wipers return to their park position the switch changes over and the motor stops.

So if you got inside, brought out the motor wire and used the in-built park switch to control a relay which replicated the functioning of the park switch, you'd remove the motor current from the park switch's flimsy contacts.

You'd still need the parking switch (its built into the power socket anyway) but it would be less likely to fail.

Sounds like a good, do-able modification.

A.






mars said:

I wonder if there's a way we could isolate the self park switch from the higher currents using a relay... If I had time I'd look into it. In fact, if I hadn't already resolved the problem I reckon it'd be fairly trivial to resolve.

mars

8,735 posts

215 months

Sunday 29th April 2007
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Depressingly, I reattached the battery yesterday having replaced my alternator (the reason the car was off the road to begin with) and my wipers still don't self-park. The switch can't have been the problem.

I'm now faced with having to take the wiper motor off altogether I suppose. Any clues as to the problem before I go that route?

alinton

965 posts

237 months

Sunday 29th April 2007
quotequote all
If the switch is definitely OK, i.e. the contacts are not burnt and the little plastic pin is not broken, then you need to check that the motor is getting its positive ignition feed.

That supply should be there when ign is on.

A.



mars said:
Depressingly, I reattached the battery yesterday having replaced my alternator (the reason the car was off the road to begin with) and my wipers still don't self-park. The switch can't have been the problem.

I'm now faced with having to take the wiper motor off altogether I suppose. Any clues as to the problem before I go that route?

mars

8,735 posts

215 months

Monday 30th April 2007
quotequote all
I replaced the switch with a brand new one. The motor works but just parks exactly wherever it is when you shut it off. Doesn't that imply it has all the right voltages?

I was trying to work out how it all operates yesterday. The steering wheel button connects to a black box above the passenger footwell which I assume turns the sequential nature of the button into intermittent/on/fast/off for the wiper motor. As all of these functions are working, I assume the black box is doing its job so the only thing that probably isn't working is the new switch. Perhaps there is something on the wheel inside the wiper motor gearbox that is not engaging with the new switch? Looks like I'll have to get it all out again.

alinton

965 posts

237 months

Monday 30th April 2007
quotequote all
The control box outputs a voltage which is constant when in continuous mode or intermittant when in intermittant mode.

The +ve IGN supply to the motor provides the supply to return the motor to its rest position when the control voltage is removed.

If you hold down the wash/wipe button what happens? Do the wipers move part way over then stop? If so then you're not getting the +ve IGN supply to the motor.

Test it with a meter on the connector.

A.


mars said:
I replaced the switch with a brand new one. The motor works but just parks exactly wherever it is when you shut it off. Doesn't that imply it has all the right voltages?

I was trying to work out how it all operates yesterday. The steering wheel button connects to a black box above the passenger footwell which I assume turns the sequential nature of the button into intermittent/on/fast/off for the wiper motor. As all of these functions are working, I assume the black box is doing its job so the only thing that probably isn't working is the new switch. Perhaps there is something on the wheel inside the wiper motor gearbox that is not engaging with the new switch? Looks like I'll have to get it all out again.