having changed a brake light in my w210 e320cdi estate 2002 due to finally being fed up with light fault sign in dashboard, a strange number of things then happened:

ABS BAS EPS warning lights came on, tested brakes in car park and they seemed fine
When braking with no sidelights on, brakes worked but one headlight also came on at same time
When braking with sidelights on, no brake lights worked at all...nothing, and it made for worrying driving
When switching off car and taking out the key, the engine kept on running, until i opened the door/took foot off brake.

As I am a maths kind of guy i knew that all this stuff must be connected and that the car brain must have gone funny. I took it to MB and they said it all sounded very serious. I suggested that it was just due to the new brake light but they laughed. I insisted on trying a new bulb. A miracle, all the problems went.

Recounted story to mechanic and he said he had a similar story with a sprinter van and that inserting one of the offset bulbs the wrong way round even for a moment can send out weird signals.

Moral: check your recent bulb activity before using expensive MB diagnostics

Hope this helps someone

 

that is very interesting
thanks for sharing