All I have is the part# 123 540 04 50.
FastLane only says fuse box. When I opened the cover it looks like a fuseable link. ie metal link screwed down at the ends not a standard fuse

Mine is open but I don't know what it goes to. My best guess is the ABS or cell phone option that was taken out before I got the car. It is located on top of the drivers side wheel well next to the auxillery fuse box with 2 fuses in it.

This was usually installed when the blower fuse started to pull too many amps. I have seen the bulletins in regard to this box. The fuse inside is called a strip fuse and comes in a few ratings. Yours is probably a 30A.

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Benzmac:
Donnie Drummonds
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 11 YRS