Lighting problem-Bad Earth?

[DAVEY DEE]

Hi peeps.

Got an issue with my lights:
1) When I brake the brake lights work but the side lights come on.
2) If I turn the side lights on then the brake lights are permanently on.

The bulbs haven't been changed lately & the rear cluster connectors look fine.

Does anyone know where the earth for this system actually grounds on the chassis? I thought I'd try & clean that as the 1st step to narrow things down.

Cheers.

[gruffalo]

Sounds like the earth for the rear light clusters. Does it effect the indicators as well?

My first stop would be to start at the bulbs and work forward, wiggle every thing with the side lights turned on.

Not 100% sure but I think they ultimately end up at the earth point on top of the tank but if that was corroded I would expect a multitude of other issues as well.

[FarmyardPants]

Sounds like one of your combined tail/brake bulbs, or its holder, is corroded, causing the two circuits to be joined at that point.

[DAVEY DEE]

As far as I'm aware it doesn't affect fhe indicators.

[The_Edge]

Check the Big Fuse too...

I had some really bizarre symptoms when mine was on the way out, a few years back now, but took me ages to pin-point the problem

[Jubag]

It might even be worth looking at the main earth wire from the battery terminal. I very recently had intermittent indicators and then could not start the car having only just removed it from the shed. Turned out to be a VERY bad earth connection on the battery terminal. All good now.

[DAVEY DEE]

Connections, bulbs etc all look fine.

Does anyone know where this part of the electrics earths to the chassis please?

[gruffalo]

I think it is the earth point behind the helmet holder.

[DAVEY DEE]

Cheers thankyou.

[DAVEY DEE]

All sorted.The lovely fitter at work fixed it for me.All the bulbs were working but a brake light bulb was short circuiting between the two filaments.....I would never have found that but he knows how to work those electrickery boxes with prongs !