Can someone shade some light on this issue I am having? I recently got an error code that says third brake light out. The brake lights in the tailights work fine so I am trying to find out if the third brake light itself has a fuse for it. Can someone please let me know if so and the location of the fuse and assigned #. My car is 2006 mercedes cls 500
I recently got an error code that says third brake light out. The brake lights in the tailights work fine so I am trying to find out if the third brake light itself has a fuse for it. Can someone please let me know if so and the location of the fuse and assigned #. My car is 2006 mercedes cls 500
No Sir. There have been no traditional fuses for the exterior lights on MBs for the past 10 years. Protection is by 'electronic fusing' at rear SAM N10/2.
You did not say if your 3rd brake light is working or not.
Did you not find a fuse map stowed in one of your fuse boxes?
Thanks for quick response and sorry for not explaining clearly . The brake lights on the taillights work fine but the center 3rd brake light thats on the rear deck is not working which is causing my cluster on my dashboard to say 3rd brake light not working. Also I can't find a fuse map
OK. Typically the fuse map will be folded up and clipped inside one of the several fuse boxes. It's worth having a search - if only to familiarize yourself with all the locations.
All the rear 'stop lamps' are driven from the same switch so it must be the 3rd brake lamp assembly that has failed. If it is anything like my W209 CLK it is a strip unit that can fracture - but at least yours is not on the trunk lid getting regular shocks.
Can you DIY simple stuff? If so I can post the WIS instructions here to change the light assembly. I would need to know if your model also has a Electric roller blind for the rear window, as that also has to be removed before the rear shelf can come out.
I asked you whether the lights had actually failed, as it isn't unknown for the cluster information to be wrong. This is when the exterior light has not failed but there is a high resistance at the socket which misleads the diagnostic light check routine performed at switch-on.
Hi Keyhole,
I was reading this post since I have a similar problem with my 2005 CLS 55 AMG. The 3th brake light stopped working and the error message shows up in the display. I have removed the left side cover in the trunk to look for the wire that comes from the 3th brake light and where it is connected, but I can't find it. Do you have any suggestions?
Regards,
Rob
I believe you need to remove the rear seat and back deck to get to it. If you have the auto screen that raises from the deck it's gonna be labor intensive (a/k/a a real pain in the a--). Good luck.
I had similar problem. 3rd tail light lid up sometimes and sometimes it was out. There's a fuse box in the trunk and there are 6 relays. The bottom one is for the 3rd tail light. I replaced that and it's been working fine ever since.
First I measured mine, but it seemed to be fine. But later I realized that the problem isn't there always and the room temperature may affect to the relays function if there's a problem. A new relay costs less than five euros, so not a big investment to do.
Keyhole, you are right in that all brake/stop lights are on fuse #60 . I also have a W209 CLK with the third brake light in the trunk lid. The original one did break at the mounting studs and was replaced by the dealer about five years ago. It has stopped working and I would like to know how to test or replace it. One of the above posts mentions replacing the "A" relay in the trunk fuse block. Do you know if this is a good solution and whether I can order this relay from the dealer? Thanks, Kwikdave
I replaced the relay and it did work several days without any problems, but then the problems started again. The relay must have somekind of role in this since everything worked fine for a while. I guess the problem must be that something strains the relay which starts to give up.
I'm not an electrician and have no idea is my hypothesis even plausible. However, I'm out of ideas.
Have third brake light problem on my 2008 cls320. Changed the relay mentioned, no help, bought new light assembly (paid it dearly at dealers) and changed it, still not working. Checked the old lamp assembly by connecting it directly to 12v, it works. So, the wiring must be the problem. Can anyone help? Please!
Hi, I was reading this trend, but didn't answered my problem, I have the 3rd brake light alert in the dashboard but actually the light is working fine. I removed and replaced the light and is working good and the alert went off for a couple hours, then appears again. I don't know what could cause this. My car is a CLK500 2007.
as Koenigstiger mentioned, you have a wire harness problem, that's why the error comes on and goes off next.
Just check the Wire harness, you'll be surprised !
Everything worked fine on my CLS, sometimes like you, the 3rd Brake Light alert, or the left Light of licence Plate, till i couldn't open the trunk lid ... only using the reserve key of the remote keyfob.
When i cheked the harness, i had 2 wires cut and 4 damaged !
I solved this problem on my 2009 CLS 550. 3rd Brake light not working. Started with a plan to replace the light. Disassembled everything IAW the posts on this form to get the rear deck and light on the bench. Tested the light with a 12 volt source and it worked. Reassembled everything up to the back seat install. Stopped there and tested the circuit from the wire harness plug behind the seat near the left C pillar. Found there was no continuity from the brown wire to the car ground. Installed a jumper wire from the plug to the ground terminal on the left side of the trunk. 3rd brake light worked as expected. Permanently installed jumper wire by splicing at the wire harness plug and connecting to the ground terminal on the left side of the trunk. The 3rd brake light has been working great since.
I never found a broken wire but the ground was interrupted some place. Looking back I should have tested everything once the back seat and C pillar cover was removed as stated some where on the forum. I lot of extra work but I am happy I did not buy a new light. Only cost was a piece of wire, some connectors and my labor.
About two years ago I bought my 2008 CLS 550, the trunk lid would not work and the 3rd tail light was out. I left the car with them and they isolated two broken wires located at the bend of the curved bar that holds the trunk. Recently the trunk stopped working again but first the 4rd brake light went out. Yesterday I took it all apart and found their previously repaired wires. The brown one was only twisted and taped, it had pulled off. I repaired that wire and the brake light now works fine.
The other wire was heat shrunk and seems to be fine but my trunk motor still does not work the trunk.
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