Mercedes-Benz 2002 M-Class Operator's Manual page 184

Caution!
To prevent accelerated battery discharge and a possible
dead battery, always remove the key from the steering
lock. Do not leave the key in steering lock position 0.
Notes:
A warning sounds when the driver's door is opened
while the key is in steering lock position 1 or 0.
With the engine at idle speed, the charging rate of the
alternator (output) is limited.
Steering lock
Instruments
Operation
and controls
181
Instrument
Driving
cluster display
It is therefore recommended that you turn off
unnecessary electrical consumers while driving in stop-
and-go traffic. This precaution helps to avoid draining of
the battery.
Unnecessary strain on the battery and charging system
may be minimized by turning off the following power
consumers, for example: Heated seats, rear window
defroster.
Practical hints Car care
Technical
Index
data