Should have left it alone, interior light not working now!

[Topdogpippin]

Hi I am new to the forum. I am on some other fora but for shooting of various types. Could anyone help me with this query please? My vehicle is an 05 350SL R230, I noticed the passenger side vanity light for the mirror wasn't working I removed the fitting and firstly checked the lamp, fine, put a multi meter across the holder no power, checked the mirror cover switch and the swivel contacts good continuity so it appeared to be supply, I checked the power supply to the static contacts on the moveable end of the visor and there was power but a bit intermittent. With power confirmed to these I bridged from them with shrouded leads to the fitting and I think a fuse went. I now have no puddle lamps no interior overhead lamps courtesy or map, but the main lamp can be switched on manually. Reference to this circuit refers to an 'electronic fuse' (I think MB refer to them as SAM) could anyone point me at the location for this please? A fairly good rummage around does not reveal any particularly informed information on these and their working as apparently they can be reset, so also some insight into this would be useful before I turn up shame faced at the auto electricians! Many thanks in advance TDP

 

[Ted]

Did they work previously when it wasn’t dark?

 

[Topdogpippin]

Yes they did. However I think the 'electronic fuse' may have reset itself as they are working again. Even my local MB dealer was not fully conversant with how they work and how to locate them although he did caveat by saying 'I am not the electrical fitter', but neither did my two local auto electricians!

 

[Ted]

Good stuff!
My understanding is that the ‘electronic fuse’ is simply a current limiting circuit.
If the specified current is exceeded, the drive circuit ‘folds back’ the current available until the load returns to normal.

 

[Topdogpippin]

Hi Ted, thanks for your input, much appreciated. It turns out that the fault with the vanity light is the micro switch which is behind the mirror surround, it can be heard to click but clearly the internal contact switch is worn or US. It does have an ID number which came up straight away so I have ordered hopefully to replace.