S211 Facelift High Level Brake Light Failure?

[Willber]

Hi,

Just started getting a '3rd brake light failure' message on the dash. All other lights seem to be ok, just the high level brake light on the estate boot door has stopped working.

Google doesn't turn up many results so guessing its not a common failure?

Any ideas where to start? Fuses etc?

Anyone had this before? Car is 2009 Facelift if that helps...

Thanks!

 

[Blobcat]

Broken wire in the hinge if it’s permanently off

 

[Willber]

Thanks. Was wondering if thats the most likely cause. Guess its just a case of removing trim and pulling wiring out of loom to see if damaged?

 

[Blobcat]

Thanks. Was wondering if thats the most likely cause. Guess its just a case of removing trim and pulling wiring out of loom to see if damaged?

Pretty much, the insulation may still be connected but the internal copper could well be snapped.

 

[Willber]

I took the trim out, couldn't see any broken wires obviously. Unplugged light, sprayed contact cleaner and put it all back together. It worked for a bit and then failed again.

Feel like its going to be one of those annoying faults to fix!

Might try putting some grease in connection or something?

Or replace the bit of wiring i can see and see if that fixes it before going any further into wiring loom which looks like it will probably go into headlining which would = nightmare

 

[mioba]

Get a voltmeter on the wires and at the same time a wiggle. if it spikes you will realise its the wire. You will need a helper on the brakes of course.

Grease - what for its a lubricant not a wire fixer.

 

[M80]

It may be that the load of the light is on the threshold of the SAM seeing a fault, with it working for a short time, before perhaps, the SAM isolates it.

In that case I would expect it to work for the short time after cycling the key.

 

[M80]

You will need a helper on the brakes of course.

There is obvious risk, but brake hold would overcome need of the helper.
I'm not sure I would want to do that myself tbh.

 

[Willber]

Get a voltmeter on the wires and at the same time a wiggle. if it spikes you will realise its the wire. You will need a helper on the brakes of course.

Grease - what for its a lubricant not a wire fixer.

Was just thinking like people do with battery terminals thats all.

Have tried the wire tester but it suggested no voltage. Then i sprayed the connector and it worked, this could have been due to moving the wire though also...

 

[Willber]

It may be that the load of the light is on the threshold of the SAM seeing a fault, with it working for a short time, before perhaps, the SAM isolates it.

In that case I would expect it to work for the short time after cycling the key.

Everything else works on the tailgate door (number plate lights etc) - would this happen if the SAM is at fault?

 

[M80]

I'm not suggesting the SAM is at fault, but that the SAM sees a fault on the light, or the wiring (possibly).

When the SAM sees issue it will isolate that issue. On cycling the ignition it would reset, and then retest.

 

[Willber]

Thanks. I guess I'll have to decide whether to replace the light, or the wiring. Not sure how to rule either of them out to be honest....
Not sure the light can be replaced in situ or have to remove the spoiler.

Sounds like a headache either way

 

[EmilysDad]

can you not apply 12 volts directly to the stop lamp while it's on the bench?

 

[Willber]

Cant see how to get it out from the spoiler without removing whole lot from car! Mechanic tested wiring and said couldn't get 12v so thinking its likely to be wiring.

Could replace the bit I can easily access I guess to rule that out..

 

[M80]

Mechanic tested wiring and said couldn't get 12v

If he isn't fast enough testing, the SAM may have isolated the feed.

 

[spenttherent]

Thanks. I guess I'll have to decide whether to replace the light, or the wiring. Not sure how to rule either of them out to be honest....
Not sure the light can be replaced in situ or have to remove the spoiler.

Sounds like a headache either way

It's not that difficult to remove the spoiler, had mine off not long ago

 

[spenttherent]

 

[Willber]

If he isn't fast enough testing, the SAM may have isolated the feed.

Great point! Didn't think of that. It does seem odd that it would be the wiring. There is no damage to the loom or cloth tape...

 

[Willber]

View attachment 89480 View attachment 89481

Legend! Thank you so much for this.

Going to spend some time on Saturday faffing about with it and see if I can get to the bottom of it