[keyhole]

The third brake light is a poor design - surprising coming from MB.
The problem is that the arrangement of the assembly contributes to its own
destruction (something like the Third Reich).

A bit late...but I did enjoy reading your analysis of this design problem - and especially the analogy above...

Your solution may well be a good one. However, it is clearly not suited to assembly-line procedures, so I wouldn't expect MB to use adhesives generally on future designs.

 

[niscuit]

A bit late...but I did enjoy reading your analysis of this design problem - and especially the analogy above...

Your solution may well be a good one. However, it is clearly not suited to assembly-line procedures, so I wouldn't expect MB to use adhesives generally on future designs.

While I agree that the original design was extremely poor, the redesigned one I got when I replaced my old is definitely superior. I have had no problems since installing it about a 1 1/2 years ago.

-Ryan

 

[Diksum]

assembly-line procedures

A bit late...but I did enjoy reading your analysis of this design problem - and especially the analogy above...

Your solution may well be a good one. However, it is clearly not suited to assembly-line procedures, so I wouldn't expect MB to use adhesives generally on future designs.

keyhole: glad you enjoyed it. I agree that this would not be appropriate on the assembly line. But I think any future application for this light should use the typical design - make the opening in the trunk such that the mounting studs fit through holes in the sheet metal and are secured with nuts.

 

[ellcapitan]

I just replaced mine on my (new to me) '03. On the replacement, the part number is different (by one digit...you have to actually look close) and the red lens plastic is thicker...makes the red a little "redder" on the new one... I've done as ppl here have suggested and only finger tightened the nuts. I did so while pushing in on the unit from the outside, to gently compress the gasket and ensure it is seated correctly. I also used blue thread-lock on the studs, as an attempt to prevent the nuts from loosening over time. Also, as somebody has mentioned somewhere, there is no need to drop the whole trunk lid liner. Just the rear (vertical) part in front of the light is all that's needed, gently folding it away as you work....Makes this job an easy 10 minute DIY affair. Only one word of caution though, watch out for VERY sharp edges. There will be a moment or two while your hand is crammed in there--trying not to lose the nuts into the trunk liner--that you won't be able to actually see what you're doing... It's probably good to just look around first and aquaint yourself with the areas that can slice skin.

 

[keyhole]

I was told by my MB parts guy that the last digit identifies the manufacturer. I also noticed that there was more 'meat' on the replacement assembly - presumably MB have now modified the specification.

Ref the danger of cuts from metal edges inside the trunk lid. Yes, I noticed that, but with the cover completely off, I avoided that. It only took an extra few minutes to get the entire cover out.

 

[akent99]

The "third brake light" on our 2005 CLK 320 needs to be replaced. I have read through this entire thread, and there is certainly good (and so, so useful) information here! But, I cannot find the part itself. I have used a google search, going directly to parts.com, etc., and still cannot find it.

Can anyone give to the specific link to the least expensive place to order it from? (I did try using the part number 209-820-10-56-M22, but only turned up one place, www.pelicanparts/com, and they want $166.25 for it!).

 

[Diksum]

Third Brake Light P/N

The "third brake light" on our 2005 CLK 320 needs to be replaced. I have read through this entire thread, and there is certainly good (and so, so useful) information here! But, I cannot find the part itself. I have used a google search, going directly to parts.com, etc., and still cannot find it.

Can anyone give to the specific link to the least expensive place to order it from? (I did try using the part number 209-820-10-56-M22, but only turned up one place, www.pelicanparts/com, and they want $166.25 for it!).

Here is the part number: 209-820-10-56, the price: $91.20, available from Parts.com. Probably still the cheapest unless you can get your local MB dealer to beat the price as I did. Mine had the light in stock.

Here is the Parts.com URL: http://www.parts.com/parts/2005/Mer...BENZ&model=CLK320&submodel=&vehicleid=1431043

 

[akent99]

Here is the part number: 209-820-10-56, the price: $91.20, available from Parts.com. Probably still the cheapest unless you can get your local MB dealer to beat the price as I did. Mine had the light in stock.

Here is the Parts.com URL: http://www.parts.com/parts/2005/Mer...BENZ&model=CLK320&submodel=&vehicleid=1431043

Thanks much Diksum! Really appreciate it.

 

[akent99]

Thanks much Diksum! Really appreciate it.

Well, I ordered the part yesterday, from parts.com. Total cost, including FedEx Ground Shipping ($13.68; seems somewhat "high") and Handling Fee ($2.00), was $106.88. I did send them an EMail, inquiring about where it will ship from, and also about FedEX, UPS. Got a reply this morning, that it will ship FedEx, but as to where it ships from, just said "The shipping depends on if the parts are in stock at our dealership or in a different warehouse".

 

[akent99]

Well, I ordered the part yesterday, from parts.com. Total cost, including FedEx Ground Shipping ($13.68; seems somewhat "high") and Handling Fee ($2.00), was $106.88. I did send them an EMail, inquiring about where it will ship from, and also about FedEX, UPS. Got a reply this morning, that it will ship FedEx, but as to where it ships from, just said "The shipping depends on if the parts are in stock at our dealership or in a different warehouse".

Got the FedEx Tracking Number yesterday, and it is being shipped from Illinois. Expected delivery date is Tuesday the 14th (Valentine's Day!).

 

[jasonasilver]

Easy to DIY, thanks for the great post

Thanks so much for the great advice here. The dealer wanted to charge $300 to fix this for me, but through the advice of this and other threads, I was able to fix myself for the cost of the part only. I ordered the "electrical, rear lamps, high mounted stop lamp, high mount lamp 2003-09 COUPE, 2004-09 CONVERTIBLE" from parts.com for $106.88 with shipping included. This fit my 2004 CLK320 Convertible perfectly, and with pretty much zero experience working on cars, I was able to install myself in 30 minutes. Thanks again!

 

[mekump]

I just replaced my 3rd brake light assembly today on my 2008 clk350. Hopefully it fixes the intermittent warnings I've been getting about the 3rd light being out. Seems like you get one shot at putting this light in place because of the adhesive gasket. On mine it doesn't seem like the top part of the light went in as far as it should have so I am seeing some of the gasket. Tried taking it back out, but I think that may have made it worse. The bottom looks good and flush.

Thanks for the diy instructions.

Mike

 

[Diksum]

Mike:
Doesn't sound right. Might be upside down. If you had fitted the light before you removed the paper from the gasket you would have had a better chance of seeing the fit. If you use the solvents I recommended, you might be able to remove the light/gasket and keep the adhesive intact. If not, clean everything off the light and just use some RTV where the gasket was. You don't say whether you used my RTV mounting method. Either way, the RTV should make a satisfactory seal.

 

[mekump]

Diksum,
Thanks for the reply. The light assembly can't go in upside down, since the electrical plug for the light assembly is on the driver's side. I agree with you that I should have tried fitting it in place before pulling off the paper from the gasket, but I didn't think there was going to be a problem. The part number on the assembly that I removed matches the new one. I didn't use the RTV mounting method because I replaced the light for an intermittent dash warning not because of physical damage to the lens. Looks like I will need to remove the light and try again. Not sure what I will do different this time to get a better fit. BTW, what kind of RTV did you use?
thanks,
Mike

 

[Diksum]

Mike:
I don't understand your comment about the plug. As I recall, the cable and plug on mine could have reached the socket on the light no matter how the light was oriented. The RTV I used was ColorPlace Clear All Purpose Silicone Sealant from Wal-Mart in a cartridge that fits into a standard caulking gun. Any clear RTV in a tube should be OK.
You didn't say whether the dash warning fault was corrected with the new light. Hard to believe the old light had gone bad considering the projected life of the LED's. Did you look at the connectors on the light or car to see if they could be corroded? Did you ask your dealer if there was any warranty on the old light (not likely)? Let us know how you make out.

 

[mekump]

Diksum,
The electrical plug wiring is routed such, that it would only reach one side of the lamp. It wouldn't be long enough to reach the plug on the light assembly if it were installed on the drivers side. The original light was obviously installed this way as well. They must have made some changes to that area of the car by 2008? I also noticed that you really can't over tighten the nuts that hold the bracket, because they feel like they bottom out w/o too much torque. The dash warning was intermittent so I don't think it was a LED type failure but maybe a bad connection on the pcb that the LED's are mounted to. When I first started getting the dash warnings, I told the dealer about the problem when I had the car in for maintenance. They were unable to reproduce the failure so nothing was done. In the last 2-3 weeks the problem was getting worse, but still intermittent. I figured a good starting place would be to replace the light assembly. I drove the car today and so far no warnings (fingers crossed) hoping the light assembly was at fault. The pins on the plug and on the light assembly side looked clean.
thanks,
Mike

 

[eddyther]

Mike:
I don't understand your comment about the plug. As I recall, the cable and plug on mine could have reached the socket on the light no matter how the light was oriented. The RTV I used was ColorPlace Clear All Purpose Silicone Sealant from Wal-Mart in a cartridge that fits into a standard caulking gun. Any clear RTV in a tube should be OK.
You didn't say whether the dash warning fault was corrected with the new light. Hard to believe the old light had gone bad considering the projected life of the LED's. Did you look at the connectors on the light or car to see if they could be corroded? Did you ask your dealer if there was any warranty on the old light (not likely)? Let us know how you make out.

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?.

 

[keyhole]

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?.

Certainly not a fuse here. The exterior lights on a W209 have 'electronic protection' from within rear SAM.

Maybe a circuit break inside the 3rd brake light assembly. Is it cracked?

 

[AmAtoL]

Guys, if you have the high level brake light not working at all, check to see if there is something else that isn't working, typically the boot light or number plate light/s.

In either case I would check the wiring harness where it is routed along the boot hinge, it will break where it terminates the hinge, just open up the outer tape for a better look if nothing is obvious. It usually is not far from there.

 

[mekump]

For me, it was only the 3rd brake lamp that wasn't working. It's only been a little over 1 week since I replaced the light assembly, but so far no warnings.
Mike