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C63 two battery's?

Since you said that I've been looking none stop! Think I'll set up a sleeping bag on the windowsill...
 
I did, surprisingly!

To my disbelief the car even started this morning, although it did sound like it struggled a little, and the battery was only running 11.4 volts, 12.8 when I left it last night, so we still appear to have an issue it seems.

I shall have a look Into this current draw once I motivate myself!
 
I had a similar issue with one of my earlier cars [non-Merc] - it turned out to be the illuminated mirror in the passenger sun visor, which wasn't properly switching off when 'shut'. Other possibles are things like 'puddle' & boot lights which depend on mechanical contacts......

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The boot light seems to be fine, I'll check those Mirrors though!

Here is what I've found, not so easy to pinpoint as I first thought!

So, connected it all up, left it for a while and found it was drawing 3.7 amps or so, on removing the fuses here are the main culprits:

Fuse 14 - 0.4 amps - abs/Asr/esp
Fuse 16 - 0.1 amps - abs/Asr/esp

Fuse 15 - 0.2 amps, not on sheet
Fuse 17 - 0.2 amps - auto dim mirror

Fuse 22 - engine electronics - 0.6 amps
Fuse 27 - engine electronics/ fuel pump, 0.5 amps

Along with some other small amounts being drawn from other fuses, but those were negligible.

However after removing all those that left me with roughly 1 amp left that wouldn't disappear, even after removing all fuses from the trunk fuse box, the engine bay one, and drivers cockpit area...


My dilemma now is, are those above the causes, or is it the 1 amp of draw I can't seem to locate, and how do I go about fixing it?
 
Right, had the car in merc today, and they have confirmed it's the rear SAM module at fault?

Can anyone confirm if this sounds right? Done a search but not heard of it cAusing battery drain :/
 
Faulty SAM module caused battery drain on the W203 so it sounds likely to me.
 
Let's hope so, cos it's not cheap by any means, hopefully it may fix the none working lumbar support buttons on it as when I press them I can hear the relays clicking like mad in the rear fuse box which I believe is the Sam module, or part of it?
 
One other thing, I've been reading a couple of topics regarding the rear Sam, with people saying not to jump start or boost the car, as this can damage the rear SAM module, apparently even the battery dying can...Surely not? Also disconnecting the battery can, so a
Slave battery is needed when removing or replacing the battery

So my question is, if my battery ever does die again, what's the best way to get it started again without damaging the module, connect to a charger whilst the battery is still in the car?

What's the best type of charger to use if so?
 

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