Rear Lighting Problem

MaverickTDi · Sep 22, 2014

To cut a long story short every time I press the brake pedal the 'brake light' indicator comes on. Having checked the operation of the entire suit of rear lights I found there to be no fault. The only thing that struck me as odd is how the drivers side rear side/brake light is a lot brighter than the passengers, see pics;

Passenger side

Drivers side

As you many appreciate this is getting quite annoying as every time I drive the car the warning appears. Can anyone explain why the drivers side bulb is brighter? I've consulted the owners manual and checked the fuse (although it must be working as I'm getting light), checked the electrical connector and all seem fine?

Any suggestions?

MaverickTDi · Sep 22, 2014

Update; Having looked more closely at the passengers side rear side/brake light bulb the second filament had melted which explains the fault indicators every time, I've replaced and all is good, no fault indicator when a depress the brake pedal. However, the drivers side side light is still noticeably brighter? When you now depress the brake pedal you do see a small increase in the brilliance on the drivers side but it's almost as if the drivers side side light has twice the power?

crazy88 · Sep 22, 2014

I have the exact same issue on mine (brake warning symbol, but only occasionally so I never thought it might be the filament). I'll check the bulb tonight when i'm home.

As for the issue of being brighter, i've not noticed but i'll look when it's darker. Last time I looked it was really sunny so hard to notice any difference as much.

MaverickTDi · Sep 22, 2014

When you look in your manual there's 2 light indicators you can get;

Brake lights;

Dipped headlights or rear lights faulty;

Given that your saying your fault is intermittent I would suggest it's not a bulb as it would simply not work unless the bulb is literally hanging on inside the holder? Perhaps check that all the bulbs are secure in the holder?

If you remove the holder from the light cluster and just have them hanging down and turn on your lights, you can easily see the difference. When I refit everything and stand back and look at the rear lights, at night, it looks like my rear fog light is on permanently?

crazy88 · Sep 22, 2014

It's the brake light symbol i'm getting. Maybe my brake light switch is dodgy also? I'll check the bulbs, and maybe put a new one in again to eliminate that and then go digging elsewhere!

aragorn · Sep 22, 2014

Replace both lamps with new ones.

And make sure you use the correct twin filament lamp.

Also, bulb monitoring also looks at the centre brake like IIRC, so if you've got a few lamps out in that, you'll get the warning too.

Oranoco · Sep 23, 2014

Mine kept giving the brake light warning on the DIS a year or so back. Checked bulbs and they were fine and it kept coming up. After checking and rechecking the bulb packed up. New bulb in and the DIS has been fine since. Odd one to say the least, maybe my DIS is psychic lol

aragorn · Sep 24, 2014

Its pretty simple really, the bulb monitor simply measures how much current the lamps are drawing. If they arent drawing enough, it brings a warning on.

I guess sometimes, when a lamp is near failure, the degraded wire filament alters such that its no longer drawing the full 21w, and the unit detects this, thus pre-empting the eventual failure.

This is why in my post above, i said to just replace both lamps. Even if they appear to work, just get them ruled out by fitting nice new ones.

MaverickTDi · Sep 24, 2014

aragorn said:
Replace both lamps with new ones.

And make sure you use the correct twin filament lamp.

Also, bulb monitoring also looks at the centre brake like IIRC, so if you've got a few lamps out in that, you'll get the warning too.

I had the same train of though as you mate. I replaced both lights with brand new ones from the same pack but still the drivers side appears brighter? They are both double filament too.

I just find it annoying that at night time it is noticeably brighter than the passengers side.

The indicator has gone out now but I just have 2 varying degrees of brilliance. Which seems to contradict the monitoring functionality of the system itself as for there to be a brighter light there must be more current drawn.

crazy88 · Sep 24, 2014

Replaced both bulbs on mine and it all seems fixed now, so as mentioned it must have been a bulb on the way out? The brake light still worked fine. No noticable difference in light output at the moment.

I gave it a test on the driveway and it seems fine, but i'll see what happens after i've had a proper drive.

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Rear Lighting Problem

MaverickTDi

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MaverickTDi

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crazy88

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MaverickTDi

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crazy88

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aragorn

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Oranoco

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MaverickTDi

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