W212 Facelift rear LED fault

[ph47mf]

I spotted the left tail light (the one on the boot lid is fine) was out when I was getting something out of the boot. I tried to find a replacement but it seems like all the major parts companies don't sell replacement, in fact they don't even list 'rear light' etc. I am not even sure whether I should look for LED, a bulb or a whole unit.

I took a closer look the other day and the unit seems sealed. As I was messing about with it, giving it a few obligatory whack, to my surprise it came back on! However I tested it again (as in whacked it a few more times), it would go on and off but on surface I couldn't see any loose connections and the unit seems secure.

1) Any of you had this problem and know a solution?
2) The LED is working now, but I want to look for a plan B, if the LED goes again, where can I find the replacement LED? Don't say I have to replace the whole unit every time that goes.

An example of the light on my car -

 

[richard]

Mercedes only sell it as a whole unit. They are different for LHD and RHD (in whether they have the foglight LEDs etc).
I'd get one from a breakers (i.e eBay easiest) ?

 

[ph47mf]

Thanks Richard.

The light works 90% of the time and when it doesn't I just need to give it a punch. I managed to find a video on Youtube that's pretty much the same.

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Any idea on the cause of this?

 

[richard]

Well i'd take it apart and re-solder the board.

 

[supermonkeyman]

Take it back to the dealer

 

[ph47mf]

Dealer looked at it and said it needs a whole new unit as they can't get into it and want to charge £500 and he said he would 'kindly' fit it for free.

Part of me is thinking it still works (just need a good bang from time to time). Anyone know someone who refurb these units? £500 for a rear light seems a bit steep, £10 bulbs were what i have been buying for other cars.

Is this a MOT failure? it's just faded, not out.

 

[Crespo]

You needs to split the light Use a heat gun around the outside edge and use a knife and screwdriver to prize it apart Then find out what is loose, re-solder it and then reseal it with silicone. I've opened plenty of headlights using this method Granted never a tail light but the process is identical. The rear are sealed for life as it is LED and not halogen and should last the life of the vehicle. In some cases a fault occurs unfortunately Due to the nature of the lights, a simple bulb change is out of the question . The above will take you between one to two hours depending on how patient you are and will be free rather than £500

 

[Crespo]

Excuse the poor grammar my phone seems to be having a fit

 

[ph47mf]

you're not based in the midlands are you crespo? fancy doing it for money?

I wish i have the know-how and tools to do this. It took me a while just to figure out where all the screws are to remove the damn thing.

 

[Crespo]

you're not based in the midlands are you crespo? fancy doing it for money?

I wish i have the know-how and tools to do this. It took me a while just to figure out where all the screws are to remove the damn thing.

Sorry, I'm in Bournemouth.
It really shouldn't be very difficult to do There is a guy called Trups Who is on the Audi forums and is also on Facebook. He modifies lights and this would be a walk in the park for him. I'm sure he's midlands based as well. He may be able to sort it out for you, or worst case scenario you could send it to him and get him to repair it. His turnaround is pretty quick

 

[Crespo]

This is the guy.

EM Tuning - Automotive Industry UK Based Company

 

[ph47mf]

i have emailed him.

Thank you Crespo.

 

[GLK]

This is the guy.

EM Tuning - Automotive Industry UK Based Company

Thanks for this, I was looking into modifying my headlights, even did a test run on a [broken] headlight unit, kindly donated by David Richardson but chickened out facing the removal of the sealant in my actual headlights ... Might re-visit the matter as this chap is local (judging by the phone number).

 

[Crespo]

Thanks for this, I was looking into modifying my headlights, even did a test run on a [broken] headlight unit, kindly donated by David Richardson but chickened out facing the removal of the sealant in my actual headlights ... Might re-visit the matter as this chap is local (judging by the phone number).

He's done so me amazing work. He's very well regarded on the Audi forums and he can make pretty much whatever you have in mind

 

[cheddar]

Usually if you can get these lights apart, they are repairable, but unlike headlamps, the rear lamps are normally plastic-welded together and not possible to dis-assemble without ruining the whole thing.
This goes for other manufacturers too EG Audi, BMW, etc.
I sometimes play with trying to fix a failed one after I’ve replaced it with a new one for a customer, but this usually results in patience being exhausted and it getting thrown in the bin.
Often I find the reason of failure is corrosion on the circuit board, despite the lamp appearing damp-free from the outside.

 

[aheinonen]

There is no need to take the rear lamps a part. Here is a way how to fix them. This lamp is from LHD car and this lamp is from left side "view from behind". Those should be pretty similar in RHD and LHD cars as far as i know.
You can cut these "service holes" where you get access to these three connectors witch usually are the origin for the problem. Just solder with tin those three components and you are good to go.
I used dremel to cut those service holes and vacuum cleaner was sucking the plastic chips whole time i was cutting, inside the lamp remained clean.
You can glue the plastic peaces back on it or just use some strong tape to cover the holes.
The whole job took about 45min and i saved 350€

 

[st13phil]

Brilliantly helpful - what a great first post!

Welcome to the forum

 

[ShaunB]

There is no need to take the rear lamps a part. Here is a way how to fix them. This lamp is from LHD car and this lamp is from left side "view from behind". Those should be pretty similar in RHD and LHD cars as far as i know.
You can cut these "service holes" where you get access to these three connectors witch usually are the origin for the problem. Just solder with tin those three components and you are good to go.
I used dremel to cut those service holes and vacuum cleaner was sucking the plastic chips whole time i was cutting, inside the lamp remained clean.
You can glue the plastic peaces back on it or just use some strong tape to cover the holes.
The whole job took about 45min and i saved 350€


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Fantastic post.
Do you just put fresh solder on both ends then, it is visible that this is the problem?
One of my tail lights as decided to not work anymore. I have a replacement ordered from Mercedes Grimsby at a fairly reasonable price. But it would be good to repair the broken unit and reclaim a few quid for it on ebay

 

[Uky]

(A bit O.T.)

I was about to suggest the solution that aheinionen described with pictures.
Have done this a few times with some 3rd brake lights that when mounted
on the rear boot suffers from water ingress due to bad/dried up gaskets.
MB does not sell the gasket as a separate item as it is "pre-glued" to the
red plastic. After repair and using conformal coating urethane lacquer on the circuit
board, the assembly has been re-fitted and sealed using thin curing silicone.
(Yes - be careful when selecting brand since some of them can dissolve the paint)

It could be a good idea to replace the surface mounted resistors with axial
versions (of equal power rating) simply because they withstand thermal
stress better. (Mount them in an "S"-position).

 

[Lal]

Hi there is a guy in Birmingham that exchanges them for u £75 I paid him. Took about 5mins...

His number - 07946661234