See also:

Cleaning the seat belts
Use clean, lukewarm water and soap solution. Do not clean the seat belts using chemical cleaning agents. Do not dry the seat belts by warming them above 176 ‡ (80 †) or placing them in dire ...

Mercedes-Benz M-Class Owners Manual
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SmartKey
0. To remove the SmartKey (shift the transmission to position P) 1. Power supply for some consumers, such as the windshield wipers 2. Ignition (power supply for all consumers) and driv ...