Rear lights and indicators not working, front all OK

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New Member
Jun 8, 2012
c220 cdi avantgarde
Hi all, hopefully this is something simple.

My 51 plate C220 CDi automatic has recently developed this issue. It is pure luck whether the rear indicators and lights come on - the front set are all fine.
Sometimes the indicators flash when the car is unlocked using the key fob, and other times not. When dark/low level light the rear lights will come on as normal at the same time as the indicators when they do decide to operate, otherwise not.

I cannot see any corrosion in the rear light clusters including the multi wire connectors and bulbs appear fine. I'm hoping this may be a a common issue with a cost effective solution as just resolved the very laggy acceleration and kick down by cleaning the MAF sensor and changing the air filter.

Hope someone can help.

Hi I had problems with my rear indciators and after spending a day testing all the wiring it turned out to be the rear sam unit I got a used unit from the breakers an found it easy to change and lights work once again.
In response to rear light problems, I offer the following experience :-
I have a 2009 C250 amg sport. A few years back I decided to fit reversing sensors. Selecting power from the existing rear white light circuit all proved 100% when selecting reverse gear. A few months later I needed to replace a blown bulb in the rear cluster. Whilst the cluster was removed for ease of bulb change, I separated the electrical cluster feed connector, only to find that the negative return pin was discoloured and the plastic surrounding it had melted.
NB this problem also existed on the opposite rear cluster connector.
I initially assumed that I may have caused the problem whilst adding the reversing facility.
Before joining the UK MB in Sept. 2015, I searched for an answer to my problem and just by chance found myself on the USA MB website. My melting problem was clearly highlighted as a major issue with some USA merc cars actually going on fire.
The USA merc owner discussing this problem pointed to the fault being due to the return earth (BROWN) wire and pin connection being unable to carry the level of current when by coincidence many of the rear bulbs were in use at the same time. The solution offered, which I duly applied to my C250, was to run another return earth wire in parallel from both rear light clusters earthing strip to nearby earthing points. From the USA thread it was mentioned that MB dealers in the USA were made to make amendments and MB provide compensation for damage caused by this wiring issue. However, I understand that MB UK have not accepted responsibility on this problem.

Trust the above info. might be of some value if experiencing problems re. the rear light cluster unit other than simple blown bulbs.
Sounds like SAM issue.

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