BMW Accessory plug


Can anyone tell me which way the wires go into the Bmw accessory plug, "the one that plugs into the bike socket"

the are 2 terminals inside the plug, one is slightly longer then the other, I need to know which is the live and which is the earth.

Regards Dragon
I'd like to know this too.

I'm trying to resurrect a vintage GPS without blowing it up with a reverse polarity whoopsie.

Here's a pic of the offender.

It's a £7.98p accessory!

Does anybody have the gen on the polarity issue?


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As a rule of thumb with these sort of plugs....its normal for the centre pin to be + and the outer or sleeve to be -

I think
Bung it in the socket and test with a multimeter for +ve and/or negative.
Don't help much if you haven't got a multimeter though:)


Convension says that the smaller one will be the positive one. I have slightly different plugs but the smaller one on mine is positive. Best way to test if you don't have a multimeter is to get a bulb, put on wire on one terminal to the bulb and the other to the frame to the bulb. If the blub does not light up then you're on the -ve terminal of the plug or the bulb is blown.
The inside pin is +12V
100% sure :)

Maybe try one of these next time, they keep the cable from sticking out:


It got mine from Cyclegadgets for $9.95
MiGSel is wise...

MiGSel said:
The inside pin is +12V
100% sure :)

It would be rollickin' daft, it would, to put the sparky to frame metal bit on the bare outside on a -ve earthed bike.

I should've thought it through, logical like.


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