Jump Starting - Mercedes-Benz 420 SEL 1989 Owner's Manual

Jump Starting

If the battery is discharged the engine
can be started with jumper cables and
the (12 V) battery of another vehicle.
Proceed as follows:
1. Position the vehicle with the
charged battery so that the jumper
cables will reach, but never let the
vehicles touch. Make sure the
jumper cables do not have loose or
missing insulation.
2. On both vehicles:
• Turn off engine and all lights and
accessories, except hazard
flashers or work lights.
• Apply parking brake and shift
selector lever to position " P" .
• Be sure the battery vent caps
are tight. Place a damp cloth
over the vent caps, making cer­
tain it is clear of all moving
parts.
3. Clamp one end of the first jumper
cable to the positive (+) terminal on
the discharged battery and the
other end to the positive (+) termi­
nal on the charged battery. Make
sure the cable clamps do not touch
any other metal parts.
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4. Clamp one end of the second
jumper cable to the grounded
negative (-) terminal of the charged
battery and the final connection to
a grounded heavy metal bracket in
the engine compartment or on the
engine of the disabled vehicle.
Make sure the cables are not on or
near pulleys, fans, or other parts
that will move when the engine is
started.
5. Start engine of the vehicle with the
charged battery and run at high
idle. Then start engine of the dis­
abled vehicle in the usual manner.
6. After the engine has started, re­
move jumper cables by reversing
the above installation sequence ex­
actly, starting with the jumper cable
connected to a heavy metal brack­
et in the disabled vehicle's engine
compartment. When removing each
clamp, make sure that it does not
touch any other metal while the
other end is still attached.
Important!
A discharged battery can freeze at
approx. -1 0 °C (+ 14 °F). In that case
it must be thawed out before jumper
cables are used.
Jumper cables specifications:
• Minimum cable cross-section of
25 mm2 or approx. 2 AWG
• Maximum length of 3500 mm
(11.5 ft)
Warning!
Never lean over batteries while
jump starting, you might get
burned.
Battery fluid contains sulfuric
acid. Do not allow this fluid to
come in contact with eyes, skin,
or clothing. In case it does, im­
mediately flush affected area
with water, and seek medical
help.
A battery will also produce hyd­
rogen gas, which is flammable
and explosive. Keep flames or
sparks away from battery, avoid
improper connection of jumper
cables, smoking, etc..