Brake light issue, also left tail light goes off when braking

[iambigred]

I bought a 2004 Smart Roadster a few weeks ago. Loving it so far, although I'm currently having a few issues.

Last week my colleague told me that my left brake light was out, so I ordered some replacement bulbs which arrived today. I tried replacing the bulb - but it's still not working. :sad:

On closer inspection, the left rear tail light also goes out when pressing the brake pedal. So at night all that is illuminated on the rear whilst braking is the centre high-level light, the right tail light and the right brake light. Indicators work fine. I've also noticed that the radio backlit display will dim/flicker slightly whilst braking.

Any ideas what may be causing this? This doesn't sound like the typical symptoms of a brake light switch problem.

Any advice would be greatly appreciated!

Alex

[Evilution]

Re: Brake light issue, also left tail light goes off when braking

Either you bought the wrong bulb, fitted it badly or the short wiring loom from the car to the bulb holders is corroded and short circuiting.
Check the bulb is fitted properly. Look at the pins on the base and make sure they match up with the holder.

[iambigred]

Re: Brake light issue, also left tail light goes off when braking

Thanks, I will check the loom. The bulb I've got is a P21/5W 380 and looks identical to the existing bulb. I'm confident that I've replaced it correctly, I successfully unseated and replaced the tail light and indicator lights, so brake light should be no different.

How long is the loom from the lights? Where does it connect to? I'll have another look in the daylight tomorrow.

[problemchild1976]

Re: Brake light issue, also left tail light goes off when braking

Stating it's identical to the one you removed doesn't mean it's correct though considering it didn't work before

I'm sure you will find the fault and at least you are aware of it!!

Soooooo many cars on the roads with faulty rear lights or brake lights that stick on etc

JJ

[iambigred]

Re: Brake light issue, also left tail light goes off when braking

Soooooo many cars on the roads with faulty rear lights or brake lights that stick on etc

I know, that's why I want to get it sorted asap! Now that mine are faulty I've noticed loads of faulty lights out on the road today!

[mocelet]

Re: Brake light issue, also left tail light goes off when braking

Remember that the tail/brake bulbs have to go in the right way round. They should be impossible to put in the wrong way around because the pins are at different heights, but some people manage to get it wrong.

It sounds like you might have a dodgy earth connection, because one filament is grounding through the other when only one is on, but when both are on, neither have a path to ground. Does the left brake light work when the tail lights are off, and is it the same brightness as the right side brake light?

[Messerschmitt Owner]

Re: Brake light issue, also left tail light goes off when braking

it is also possible that one of the little lugs on the plug into the main loom is broken and causing a lack of contact! It is a back end off to check - although you may get away with just having to check the one side and you can do that without removing the whole rear end.

Now, normally on a roadie, if the lights are shorting, or not working, the fog light warning on the dash should display (dimmed) permanently.

The loom for the lights is all attached to the rear end and includes both tail light units plus the numberplate maps. Technically, there is a plug at each side plus the separate numberplate lamps. The centre light is on the main loom, so unaffected if there is a short at the rear.

What other lamps work on the rear of the car?

[iambigred]

Re: Brake light issue, also left tail light goes off when braking

This might simplify my explanation. No warnings on the dash at all.

[krassegrand]

Re: Brake light issue, also left tail light goes off when braking

This might simplify my explanation. No warnings on the dash at all.

Nice explenation!
I am sorry I cant help You more that the other guys hav allready done.

Jörgen

[madDan]

Re: Brake light issue, also left tail light goes off when braking

That shows as no brake lights working!

The RHS when braking is your fog lamp coming on!

Have you drawn it correctly?

The brake lamps are in the same part as the tail light. ie the outermost lamps

As suggested above make sure the light unit looms are connected correctly - if clip is broken use tiewrap to hold together, also check loom for damage - may have been caught on crashbar when back was refitted.

Check fuse 26

Check SAM connections additionally

[Evilution]

Re: Brake light issue, also left tail light goes off when braking

Still sticking with my original guesses. Love the pictures, definitely stealing those for use elsewhere.