Mercedes-Benz S-Class 2020 Owner's Manual page 387

384 Breakdown assistance
using the jump lead. Start with the donor
vehicle first.
Start the engine of your own vehicle.
#
Let the engines run for several minutes.
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Before disconnecting the jump leads, switch
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on an electrical consumer in your own vehi‐
cle, e.g. the rear window heater or the light‐
ing.
When starting assistance has finished:
First remove the jump lead from the earth
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point of your own vehicle and the negative
terminal of the donor battery, then remove
the jump lead from the positive contacts of
both vehicles. Always start with your own
vehicle first.
Close protective cover 2 of positive contact
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3 and close cover 1.
Further information can be obtained at a quali‐
fied specialist workshop.
Charging the 12 V battery
Connect the positive contacts of the vehicle
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and the charger with the charging cable.
Start with the vehicle first.
Connect the negative contact of the charger
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and earth point 4 on the vehicle with the
charging cable. Start with the charger first.
Start the charging process.
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When the charging process is complete:
Remove the charging cable from earth point
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4 on the vehicle and the negative contact
of the charger first and then from the posi‐
tive contacts on the vehicle and charger.
Always start with the vehicle first.
Close protective cover 2 of positive contact
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3 and close cover 1.
Replacing the 12 V battery
Observe the notes on the 12 V battery
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( page 379).
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Mercedes-Benz recommends that you have the
12 V battery replaced at a qualified specialist
workshop, e.g. at a Mercedes-Benz Service
Centre.
Observe the following notes if you want to
replace the battery yourself:
Always replace a faulty battery with a battery
R
which meets the specific vehicle require‐
ments.
The vehicle is equipped with an AGM technol‐
ogy battery (Absorbent Glass Mat) or a lith‐
ium-ion battery. Full vehicle functionality is
only guaranteed with an AGM battery or lith‐
ium-ion battery. For safety reasons,
Mercedes-Benz recommends that you only
use batteries which have been tested and
approved for your vehicle by Mercedes-Benz.
Carry over detachable parts, such as vent
R
hoses, elbow fittings or terminal covers from
the battery being replaced.
Make sure that the vent hose is always con‐
R
nected to the original opening on the side of
the battery.
Fit any existing or supplied cell caps.
Otherwise, gases or battery acid could
escape.