New Member with 3rd brake light warning

[PhilR22]

Hi guys, Thanks for letting me join. I have just bought a 2004 C200cdi 122hp with 92000 miles. I am getting a 3rd brake light warning on the dash. I also have a the right number plate light bulb out (no power at contacts) so I believe the issue could be a broken wire possibly at the boot hinge. Has anyone had this issue and if so how did you resolve it. Thanks in advance for any help.

 

[Blobcat]

Hello and welcome

Normally it’s a case of taking the loom apart at the hinge area and looking / feeling for broken wires then soldering in a new section.

 

[grahamcol]

Hi and welcome.
With my CLK (209 model) l kept getting an intermittent 3rd brake light warning too. Turned out to be the Led strip itself and l ended up replacing it. Apparently its common on my model but I'm not sure if this applies to your C class which will be a 203 model. The other lamp could just be a bulb issue. Edit just noticed you said no power at bulb contacts, so forget my previous remark.

 

[PhilR22]

Hi and welcome.
With my CLK (209 model) l kept getting an intermittent 3rd brake light warning too. Turned out to be the Led strip itself and l ended up replacing it. Apparently its common on my model but I'm not sure if this applies to your C class which will be a 203 model. The other lamp could just be a bulb issue.

Hi Graham,
Thanks for the response, the welcome and the information. I have replaced the number plate bulb with a known good one and it is still not working. I should have also been more specific - I am getting the 3rd brake light warning on the dash but the light is off constantly not intermittently.

 

[PhilR22]

Hello and welcome

Normally it’s a case of taking the loom apart at the hinge area and looking / feeling for broken wires then soldering in a new section.

Hi Blobcat. Thank you for the response and information. I was thinking it might be something like this. Have you had this problem and if so do you know where is likely to go. What I mean is should I start by taking out the liner in the boot around the bottom of the hinge or take out the liner of the boot lid around the top of the hinge.

 

[grahamcol]

Hi Graham,
Thanks for the response, the welcome and the information. I have replaced the number plate bulb with a known good one and it is still not working. I should have also been more specific - I am getting the 3rd brake light warning on the dash but the light is off constantly not intermittently.

Good luck with this. Does sound like a possible broken wire, but do bear in mind the possibility of a defective Led strip like mine. Please post the outcome on here as it helps others.

 

[dry run]

Welcome

 

[PhilR22]

Good luck with this. Does sound like a possible broken wire, but do bear in mind the possibility of a defective Led strip like mine. Please post the outcome on here as it helps others.

I will do. I will post the solution here also. Thanks again

 

[mioba]

whip the brake light led off and check for voltage at the connector to the strip.
I cant imagine a brake light and number plate light being on the dame circuit. But who knows.

 

[PhilR22]

Update: Thanks for all the replays.
I resolved the problem - Turns out it was a broken wire near the boot lid hinge.

 

[mioba]

Great you got it sorted. Well done!