[Diksum]

LED failure

I have the same problem as mekump: intermittent warnings that yesterday became permanent, the 3d rear light not lighting anymore.
You say that it cannot be a led failure because of their long life design. So what can i do before buying a new one? What can be wrong? Maybe a fuse?.

If a fuse is blown, there are likely other failures. Unless you have a wiring or connector issue, the MB system that monitors this is likely correct about the light.
While an individual LED is extremely reliable and long lived, it's not impossible for the LED ARRAY to fail. Mine failed because the broken plastic interrupted the continuity of the internal wiring. Examine the array to see if there are any breaks or cracks. If it looks bad, it is not likely you can repair it. Your only remedy is to replace it.
When I talked to my dealer, he acted as though he had never heard of a failure of this light. MB has no info on their internal dealer system that even acknowledges these failures, notwithstanding the extensive documentation on the internet. My MB parts guy certainly knew about it. Unless you're still under warranty, you'll have to eat the cost of a new light. As you can see from this thread, you can replace it yourself and save some money.

 

[pedcat]

I swapped mine out today, much thanks to the OP for the DIY write-up.

The newer light (top) seems to have a clearer, and hopefully stronger, lens:

 

[Tom33952]

Got one last week at Parts.com, about $105 delivered.

 

[rederikus]

I am just about at attempt replacement of the third brake light. I was quoted the ridiculous amount of £185.00 ($295) for replacement.

I have bought a genuine Mercedes part (A 209 820 1056) on ebay for £80 including postage. When it stops raining, I shall do the job.

keyhole's guide makes the job look really straightforward. I hope my job goes as simply as the guide suggests.

I am tired of Mercedes-Benz dealers producing telephone number prices for routine repairs. I was recently quoted a huge amount (£500+) to rectify a small internal engine oil leak. I finally had this fixed by a local garage who specialize in Mercedes for less that half the price the official dealer quoted AND, the did both sides of the engine whereas the dealer's offer was for just one side. My car has done only 34K miles and I feel that a modern engone should not be developing oil leaks at this mileage.

 

[Tom33952]

I am tired of Mercedes-Benz dealers producing telephone number prices for routine repairs. .

Yes, me too. MB has an overtly predatory attitude toward owners. At this price level I have low tolerance for the defects and shortcomings of the car, including this tail light that disintegrates upon a hard slamming of the trunk lid. This will be a one and only ownership experience for me.

 

[rederikus]

Yes, me too. MB has an overtly predatory attitude toward owners. At this price level I have low tolerance for the defects and shortcomings of the car, including this tail light that disintegrates upon a hard slamming of the trunk lid. This will be a one and only ownership experience for me.

I think that I will buy another one but I agree with you about an "overtly predatory attitude toward owners" as I too have experienced this.

My particular car, the CLK, has now cost me so much money that the pleasure of ownership has been surpassed by the cost of ownership. I feel ripped off.

 

[rudeney]

Remember, car dealerships exist to make a profit, and an authorized service center makes much more profit than the new car sales side. In fact, if it was possible to open only an authorized service center without having to sell new cars, they would be all over the place. The reality is, the manufacturers require authorized dealers to provide both service and new vehicle sales.

Dealers charge "market price" for their services. It's simple micro-economics of supply and demand. Since on average, MBZ owners tends to be wealthier and have less time to deal with auto repairs, they are more willing to pay higher prices to maintain their vehicles. My advice for anyone is to either learn to DIY, find a reputable indy mechanic, or maybe MBZ isn't the right brand for you.

 

[keyhole]

My particular car, the CLK, has now cost me so much money that the pleasure of ownership has been surpassed by the cost of ownership. I feel ripped off.

You must have been very unfortunate and bought an abused car.

My experience has been quite the opposite and apart from this 3rd brake light, nothing (other than from normal consumables) has needed replacement since my ownership started in 2006. The build quality of my CLK is amazing - and no rust either!

 

[chris_dod]

Just noticed this happen to our 2004 clk320. The lens finally broke off clean where it was slotted into the trunk opening. Looks like the replacement should take no more than 30 minutes to an hour.

Has anyone tried to put some kind of thin cushioning along the edges of the new plastic lens to maybe help absorb some of the impact? Might not prevent it from ever happening, but would certainly prolong the life before the next replacement. I think a thin film of tape around it would do. I think the opening in the trunk can still accomodate that.

Also noticed that the light itself doesn't light up anymore.

 

[Diksum]

Third Brake Light Replacement.

See my post #40 on this board.

 

[keyhole]

Has anyone tried to put some kind of thin cushioning along the edges of the new plastic lens to maybe help absorb some of the impact? Might not prevent it from ever happening, but would certainly prolong the life before the next replacement. I think a thin film of tape around it would do.

If you check post #3 you will see that the new light assembly comes with an adhesive foam strip surround that is a shock absorber. Diksum suggested also using glue, but I'm not convinced that it is necessary.

Also noticed that the light itself doesn't light up anymore.

Once the plastic cracks, the circuit can soon get damaged. Does it throw up a warning on the cluster at switch-on?

 

[a4driver]

This example works like a charm. I might suggest that you hook up the light before final installation and start the engine to make sure no warning light/message and that it lights.

 

[kwikdave]

Third Stop Light test

Excellent post for replacement of this light. I assume the steps are pretty much the same for the Cabriolet except for the wiring in the hinge. My light was replaced by the dealer under warranty several years ago and the lamp itself looks ok. Is there a simple way to test the connections or the lamp before I order a replacement?

 

[a4driver]

My outage was shown on the dash warning message. Other than a loose wire not sure how to test. A new one from RockAuto is around $100 and it's pretty easy to install. Make sure you keep a hand on the 2 nuts when loosening and tightening back on to the fixture.
Oh yes, DON'T SLAP THE TRUNK LID.

 

[Dash0528]

Please help me I cannot get it placed right pictures below

 

[keyhole]

Please help me I cannot get it placed right pictures below

No pics either...

 

[Dash0528]

I can place the 3rd like correctly

:frown(What am I doing wrong?
where exactly are the bolts supposed to go to keep the light in place? on top the holes, inside the holes what?????

 

[keyhole]

The new light assembly must be presented from the outside. The bracket should then be replaced, and when the nuts are tightened the bracket will hold the light assembly in place.. If your new light is passing right through the hole, you have the wrong part.

Assembly here is simply the reverse of dis-assembly.

 

[Dash0528]

the pictures above, I took from inside the trunk. So you are saying I need to replace it from the outside And then when I put the bolts in and tighten it, that should be it?

 

[keyhole]

As I remember it - yes. Not too tight with the nuts. Enough to keep the water out.

I think that I said it was easier to fix the connector on while the light is still outside. Have you forgotten how you took it apart?