21 replies to this topic

[Mininman_Aid]

Hi all!

This is on my other half's 1994 Cooper 1.3i


Her windscreen wipers are running the wrong way! They run in reverse then run forward, so they park vertically rather than horizontally.


To start with a fuse went, this was replaced and since then the windscreen wipers will only park in a vertical direction- i can't get them to stay flat!

I've replaced the park switch and I've tried every possible method of turning them and the ignition on and off to try and make them stay in the horizontal position, but they just return to the top position when they have power back on.

I've heard of this problem before... but have no idea how to fix it... does anyone know?


Thanks!!!

[Dan]

It's an internal mechanical problem in the wiper motor gearbox, there's no way I can think of that it could have been caused by anything electrical that has blown the fuse. The parking ramp is on the wrong side of the drive gear. Ot it could be that the wheel boxes are upside down.

[Mininman_Aid]

It's an internal mechanical problem in the wiper motor gearbox, there's no way I can think of that it could have been caused by anything electrical that has blown the fuse. The parking ramp is on the wrong side of the drive gear. Ot it could be that the wheel boxes are upside down.

Well it was all working fine before the fuse went...

I was wondering if when the fuse went, the wiper motor was in motion and something inside then went into the wrong position? I'm not entirely sure whats inside, but isn't there a disc with contacts on it which decides the direction of rotation of the motor? Could this just now be the wrong way round?

[Dan]

There isn't specifically no but I suppose the motor could have been flashed. I'm not sure if it's a permanant magnet motor or not just now. The brush plate shouldn't really decide which way it rotates, it has a third contact that adds the higher speed but it's only a brush plate really. I'll look the motor up and see what I can find out.

Although even if the motor is turning backwards, the park position should still be in the same place. The relationship between the wiper arms and the drive gear is fixed and machanical and as far as I can remember the parking ramp is symetrical.

[Mininman_Aid]

There isn't specifically no but I suppose the motor could have been flashed. I'm not sure if it's a permanant magnet motor or not just now. The brush plate shouldn't really decide which way it rotates, it has a third contact that adds the higher speed but it's only a brush plate really. I'll look the motor up and see what I can find out.

Although even if the motor is turning backwards, the park position should still be in the same place. The relationship between the wiper arms and the drive gear is fixed and machanical and as far as I can remember the parking ramp is symetrical.

Brilliant, thanks.

[Dan]

Well it is a permanant magnet motor so the field is fixed. Even if it had been flashed it would have fixed itself the first time it was powered up the right way around. The only way to run it backwards is to connect it up backwards. I was going to suggest surge damage to the switch points in the park switch from the fuse failure (although I can't see how it would cause this) but you say you've fitted a new one. Are you sure you connected up the new park switch properly? Even if it is running backwards it should still be parking properly. What caused the fuse to fail? Were the wipers stuck? I suppose if they were stuck and the motor managed to move it could have either stretched the cable (very unlikely, that's a strong cable) or spun the plate on the drive gear but again it's unlikely. I think you'll have to look inside the gearbox.

[Mininman_Aid]

Well it is a permanant magnet motor so the field is fixed. Even if it had been flashed it would have fixed itself the first time it was powered up the right way around. The only way to run it backwards is to connect it up backwards. I was going to suggest surge damage to the switch points in the park switch from the fuse failure (although I can't see how it would cause this) but you say you've fitted a new one. Are you sure you connected up the new park switch properly? Even if it is running backwards it should still be parking properly. What caused the fuse to fail? Were the wipers stuck? I suppose if they were stuck and the motor managed to move it could have either stretched the cable (very unlikely, that's a strong cable) or spun the plate on the drive gear but again it's unlikely. I think you'll have to look inside the gearbox.

I have no idea what blew the fuse. I was away at the time and my other half took it into a garage and they just tracked it down and changed it and it started working again.

It is all wired up the correct way round- I checked all the wiring both in the haynes book of lies and on my own Mini.

Its almost like the motor has become left hand drive...

Maybe the easiest thing is going to be to change the whole wiper motor? I can use the one that's currently fitted to my project car and just buy another one off ebay I guess...

[Ethel]

Park the motor then try refitting the arms in the right position.

[BoboGib]

Sounds like the garage may have taken something apart as well as change the fuse.

[Mininman_Aid]

Park the motor then try refitting the arms in the right position.

The arms park all the way at the top of the swing, so if i did that they would wipe the scuttle panel instead of the windscreen!

[Mininman_Aid]

Sounds like the garage may have taken something apart as well as change the fuse.

Yeah I did have my suspicions... but they are a good garage normally...

[Mininman_Aid]

Is there not a way of switching a couple of the wires around to make the motor run backwards... seeing as it is already going backwards this would then make it go forwards??

[Ethel]

The wipers can't go backwards - they spend half their time going in one direction and the other half in the other - they'd do the same even if the motor rotated in the other direction.

All you need is for them to stop at the bottom so let the motor park itself and fit the arms at the bottom.

[Mininman_Aid]

The wipers can't go backwards - they spend half their time going in one direction and the other half in the other - they'd do the same even if the motor rotated in the other direction.

All you need is for them to stop at the bottom so let the motor park itself and fit the arms at the bottom.

Not that simple.

If you stand at the front of the car and look at the wiper wheel poking out the scuttle and you get someone to push down on the wiper stalk and release. Whats supposed to happen is the wheel should turn anti-clockwise about 110 degrees, then go back clockwise to its original position. Whats actually happening is the wheel is turning clockwise about 110 degrees and then turning back clockwise to its original position... so if i ran it with no wiper blades and let it park, the put the blades on it, the blades would try and turn clockwise and as a result crash into the scuttle and bonnet!

[Ethel]

In that case the gear is 180 degrees out, most likely the wheel boxes are on the wrong side of the rack - or the drive gear needs turning round in the motor.

If you reversed the polarity of the motor it would just crash into the wrong side of the park switch ramp and jam.