Mercedes-Benz GLS Owner's Manual page 399

396 Breakdown assistance
with positive clamp 2 on your own vehicle
first.
During starting assistance: start the
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engine of the donor vehicle and run at idle
speed.
Connect the negative pole of the donor bat‐
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tery and earth point 3 of your own vehicle
by using the jump lead/charging cable. Begin
with the donor battery first.
During starting assistance: start the
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engine of your own vehicle.
During the charging process: start the
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charging process.
During starting assistance: let the engines
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run for several minutes.
During starting assistance: before discon‐
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necting the jump lead, switch on an electrical
consumer in your own vehicle, e.g. the rear
window heater or lighting.
When the starting assistance/charging process
is complete, perform the following steps:
First, remove the jump lead/charging cable
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from earth point 3 and the negative pole of
the donor battery, then from positive clamp
2 and the positive pole of the donor bat‐
tery. Begin each time with the contacts on
your own vehicle first.
After removing the jump lead/charging
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cable, close cover 1 of positive clamp 2.
Further information can be obtained at a quali‐
fied specialist workshop.
Replacing the 12 V battery
Observe the notes on the 12 V battery
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( page 391).
/
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
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hoses, elbow fittings or terminal covers from
the battery being replaced.
Make sure that the vent hose is always con‐
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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.
Make sure that detachable parts are recon‐
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nected in the same way.