Some weird electrics - high level break light

Hello all,

On my 2005 110 I have a strange problem.

The high level break light does not work when I press the break pedal. However, if I turn on the rear window heater or the rear wiper, it comes on and will go off when I brake.

I've checked all visible contacts and tinkered with most cables to no avail. Can anyone shed any light on this?

Regards,

JY

Electrical weirdness of this nature is almost always an earth return fault - it works when the other circuits are in use due to be able to earth through them.

Deafeners are renowned for such issues - worth checking all earth straps are present and correct.....

As BFG says, it's almost always the earths.
Looks like you got a better earth on the screen heater and wiper (common earth strap) than on the brake light.
Try just linking them up together.

Thanks both, I'll look a bit deeper!

Similar issues which I’d decided were earthing..... Any easy hints on where vulnerable earths are found that end of the chassis? Thx, A

Either on a stud or a screw at the arse end of the chassis.

If you feel flush it's worth getting a length of good cable and suitable connections and running an earth back to either the gearbox / block or direct to battery. Or at least earth everything to the rear of the chassis.

Good advice - cheers both, A