E86 rear light cluster fault

[Brouse]

Hello,

Got a curious issue with my rear light cluster. Bulb warning came on and did a walk around and found it was the nearside foglight.

I examined the bulb and it was visually fine and worked on the other side.

I ran a code reader on the car and no errors, which is both great but not helpful. It is only a basic reader so I wonder if an indy could discover more?

I ran a continuity test on the bulb socket and the pins for the connector and pin is dead and pin 2 and 3 are dead on the connector itself.

I plugged the fully functional cluster into the nearside (faulty side) and the fog didn't work either.

I also plugged the faulty cluster into the offside (functional) wiring and the reverse light became the side light and the brake light became the fog (not sure how reliable this is as a test)

Does anyone have any experience of this type of gremlin?

NB Not sure if relevant but for context the bulb warning originally led me to the sidelight which I sorted, and then came on again shortly afterwards, so dunno if that did it as I did the bulb holder mod on the angel eye to swap out the broken bulb? The bulbs look different but I was assured T4W was the right replacement.

Might of always been the fog and I happened the catch the sidelight first as assumed it was that...

Bulb warning before all of this was intermittent and is now always on.

[E86]

I think UK cars only have one rear foglight, fitted to the offside?

[Brouse]

I did wonder, odd to put a bulb in a non-live position but would explain the dead ends when continuity testing...what on earth is this error

[E86]

Maybe the other bulb is fitted for LHD cars?

It's a shame the car can't tell you which bulb is faulty when it must know... If all the other lights are working, including the brake lights, wonder if it's still the angel eye bulb causing the warning? Shouldn't it be a 10W bulb? Can you check the old one?

[Brouse]

Yea doesn't say on bulb or packet or website only mentions 12V.

A cursory google seems to put a typical T4W (233) at 4w so perhpas that's the culprit then.

Thanks E86, hopefully that sorts it.

[E86]

This and this thread say it should be a 10W bulb, so can imagine a 4W bulb could trigger a warning.

No problem, hope you get it sorted. Good to have no warning lights on the dash

[Liam22]

Maybe the other bulb is fitted for LHD cars?

It's for brake force display. If coded, will illuminate both fog lamps under heavy braking.