Fog lights come on when I brake!

[SmokinScoobs]

Hey guys,

Started happening this morning. Nothing obvious happened or set it off I think.

So the dash indicator for general lights comes on and dims the rest of the dash when I put the brakes on, even when no lights are on on the stalk. Checked all the lights, everything is OK except the fog lights are coming on when I brake.

Wait, if I turn the lights on it appears as if the brake lights are on all the time. There is a very slight increase in light when I brake, but the center light in the spoiler is on all the time.

All fuses seem good.

Any help appreciated

Cheers.

[champ]

Started happening this morning. Nothing obvious happened or set it off I think.

Have you done anything lately to the car?

[SmokinScoobs]

Nope. Been goin fine.

[RX25SE]

Sounds like a earth issue.

Try removing the brake light globes and see if it still does it.
If it does you may have lost an earth on one side.

Does it have a trailer plug?

[SmokinScoobs]

No trailer plug.
I'll try the globes tomorrow, to dark now.
Any other tips welcome.

[SmokinScoobs]

Thanks for the tip RX25SE!
Pulled both globes out, no foglight action.
Put one globe back in, no foglight action.
Put other back in problem returns.
Try just the 2nd globe in other side, problem still there.
Replace globe even though globe itself seems to work fine and filaments look OK = ALL GOOD

What an obscure problem, though turns out an easy fix.

Cheers!

:thumbsup:

[RX25SE]

Glad you sorted it.

Did the dodgy globe have a single or double contact on the bottom?

[SmokinScoobs]

double. On closer inspection it has a very slight dark haze on the glass, so possibly a bit of a short out in its guts

[SmokinScoobs]

I suppose technically it wasn't working fine, because when I turned the headlights on the brake filament was firing, and shorting through to something else, though you couldn't tell whether the low power filament was on or not.