Windscreen wiper motor

[peterux]

Hi Nigel,

I didn't use the stalk switch so I don't know, but i'm wondering if the BMW stalk switches to 'ground' rather than to B+ ? I think your wiper motor connections theory looks right to me.

...peter

[NigelB]

Originally Posted by peterux

Hi Nigel,

I didn't use the stalk switch so I don't know, but i'm wondering if the BMW stalk switches to 'ground' rather than to B+ ? I think your wiper motor connections theory looks right to me.

...peter

Hi Peter,

You're back!! I haven't seen you on here for a while. Good to hear from you.

I built up my loom as I went along so I know I am switching +12v through to the 1st and 2nd speed terminals and the fact that they work independently indicates that I'm not picking up an earth there.

One thing I thought about this morning (and I know it shouldn't make any difference) is that the 12v on pin 4 and the switched 12v to pins 3 or 5 are both from the same fused supply. I'll try using separate supplies and see what happens............................

Nigel

[MartinClan]

It's too long ago to remember much detail but I think my original explanation was correct. All the park circuit does is apply power to the slow speed connection, as the wiper switch does, except it only applies it till the park position is reached. From you explanation it sounds like somehow you are shorting to ground using the park circuit.

I used the standard bmw loom complete with wiper relay which simplified things a bit.

Cheers, Robin

[NigelB]

Hi Robin,

That's exactly what I am doing.

But I have drawn out the wiring diagram from the supply via the switch to the motor (using your diagram) and I can't work out where the earth is coming from.

It's interesting that you mention the standard loom and a "wiper relay". I found this circuit www.Vitessesteve.co.uk and have wired up my wipers the same way and now they works just fine..................


wiperdiagram by MarlinBuild, on Flickr

It's a simple change over relay that isolates the wiper supply voltage from the park supply. It works, but for me, it still leaves the question Why??

But being pragmatic, it works, so forget it.............................!!