2003 MERCEDES-BENZ SL500 start

319 Practical hints
Batteries
Batteries
Your vehicle is equipped with two batter-
ies:

The starter battery (located in the en-
gine compartment)


The battery for electrical consumers
(located in the trunk)
Starter battery in the engine compartment1Positive terminal
2Negative terminal
Warning!
G
Failure to follow these instructions can re-
sult in severe injury or death.
Never lean over batteries while connecting,
you might get injured.
Battery fluid contains sulfuric acid. Do not
allow this fluid to come in contact with eyes,
skin or clothing. In case it does, immediately
flush affected area with water and seek
medical help if necessary.
A battery will also produce hydrogen gas,
which is flammable and explosive. Keep
flames or sparks away from battery, avoid
improper connection of jumper cables,
smoking, etc.
!Never loosen or detach battery termi-
nal clamps while the engine is running
or the key is in the starter switch. Oth-
erwise the alternator and other elec-
tronic components could be severely
damaged.
Have the starter battery checked regu-
larly by an authorized Mercedes-Benz
Center
Refer to Service Booklet for mainte-
nance intervals or contact your autho-
rized Mercedes-Benz Center for further
information.Warning!
G
Do not place metal objects on the battery as
this could result in a short circuit.
Use leak-proof batteries only to avoid the
risk of acid burns in the event of an acci-
dent.

320 Practical hintsBatteries
Disconnecting the batteriesDisconnecting the battery for electrical
consumers

Unhook the luggage cover in the trunk.

Remove the trunk floor.
The battery for electrical consumers is
located in the right hand area of the
trunk (
page 289).

Use the 10 mm open-end wrench from
the vehicle tool kit to disconnect the
battery negative lead.

Remove the cover from the positive ter-
minal.

Disconnect the battery positive lead.
Disconnecting the starter battery

Use the 10 mm open-end wrench from
the vehicle tool kit to disconnect the
battery negative lead.

Remove the cover from the positive ter-
minal.

Disconnect the battery positive lead.
Warning!
G
The brake system requires electrical power
to operate.
A malfunction in the vehicle’s power supply
or electrical system may impair brake sys-
tem operation and switch it into its
limp-home (emergency operation) mode.
The same applies if battery is disconnected.
To brake, the driver must then apply signifi-
cantly greater brake pedal pressure and de-
press the pedal much further to obtain the
expected braking effect. If necessary, apply
full pressure to the brake pedal. Brakes are
only applied to the front wheels. Stopping
distance is increased! Adjust your driving
style accordingly. SBC brake system
(page 72).
Warning!
G
With a disconnected battery

y o u w i l l n o l o n g e r b e a b l e t o t u r n t h e k e y
in the starter switch and pressing the
KEYLESS-GO
* start/stop button (if so
equipped) on the selector lever will have
no effect


the selector lever will remain locked in
positionP!To avoid damage to electrical compo-
nents, always disconnect the battery
for electrical consumers (in trunk) first.
This applies even if you only wish to
charge the starter battery. Otherwise
the electronics of the vehicle can be
damaged.

321 Practical hints
Batteries
Removing the batteries
Removing the battery for electrical con-
sumers
Remove the screws securing the bat-
tery in the trunk.

Remove the battery support and brack-
et. Take out the battery.
Removing the starter battery

Remove the screws securing the start-
er battery in the engine compartment.

Lift the retaining bracket and remove
the battery.
Charging and reinstalling batteries
Charge batteries in accordance with
the instructions of the battery charger
manufacturer.

Reinstall the charged battery. Follow
the previously described steps in re-
verse order.
Reconnecting the batteries
Reconnecting the starter battery
Turn off all electrical consumers.

Connect the positive lead and fasten its
cover.

Connect the negative lead.
Warning!
G
Never charge a battery while still installed in
the vehicle. Gases may escape during charg-
ing and cause explosions that may result in
paint damage, corrosion or personal injury.
!To avoid damage to electrical compo-
nents, always reconnect the starter
battery (in engine compartment) first. !Never invert the terminal connections!!The battery, its filler caps, and the vent
tube must always be securely installed
when the vehicle is in operation.

323 Practical hints
Jump starting
Jump starting
If the starter battery is discharged, the en-
gine can be started with jumper cables and
the battery of another vehicle.Observe the following:


Jump starting should only be performed
when the engine and catalytic convert-
er are cold.


Do not start the engine if the battery is
frozen. Let the battery thaw out first.


Only use 12V batteries to jump start
your vehicle. Jump starting with a more
powerful battery could damage the ve-
hicle’s electrical system, which will not
be covered by the Mercedes-Benz
Limited Warranty.


Only use jumper cables with sufficient
cross section and insulated terminal
clamps.
Always make sure that the jumper ca-
bles are not on or near pulleys, fans, or
other parts that move when the engine
is started or running.
Warning!
G
Failure to follow these directions will cause
damage to the electronic components, and
can lead to a battery explosion and severe
injury or death.
Never lean over batteries while connecting
or jump starting, you might get injured.
Battery fluid contains sulfuric acid. Do not
allow this fluid to come in contact with eyes,
skin or clothing. In case it does, immediately
flush affected area with water, and seek
medical help if necessary.
A battery will also produce hydrogen gas,
which is flammable and very explosive. Keep
flames or sparks away from battery, avoid
improper connection of jumper cables,
smoking etc.
Read all instructions before proceeding.
!Jump starting may only be performed
on the battery installed in the engine
compartment.
Avoid repeated and lengthy starting at-
tempts.
Do not attempt to start the engine us-
ing a battery quick charge unit.
If the engine does not run after several
unsuccessful starting attempts, have it
checked at the nearest authorized
Mercedes-Benz Center.
Excessive unburned fuel generated by
repeated failed starting attempts may
damage the catalytic converter and
may present a fire risk.
Make sure the jumper cables do not
have loose or missing insulation.
Make sure the cable clamps do not
touch any other metal part while the
other end is still attached to a battery.

324 Practical hintsJump startingThe starter battery is located in the engine
compartment.
Make sure that the two vehicles do not
touch.

Turn off the engine.

Turn off all electrical consumers.

Apply parking brake.

Shift selector lever to positionP.1Negative terminal of charged battery
2Negative terminal of discharged
battery
3Positive terminal of discharged battery
4Positive terminal of charged battery

Remove the red cover from positive ter-
minal on both vehicles (
page 319).

Connect the positive terminals 3 and 4
of the batteries with the jumper cables.
Start with the charged battery.

Start the engine of the vehicle with the
charged battery and run at idle speed.

Connect the negative terminals 1 and 2
of the batteries with the jumper cables.
Start with the charged battery.

Start the engine of the disabled vehi-
cle.
Now you can again turn on the electri-
cal consumers. Do not turn on the
lights under any circumstances.

Remove the jumper cables first from
the negative terminals 1 and 2 of the
batteries and then from the positive
terminals 3 and 4.

Have the battery checked at the near-
est Mercedes-Benz Center.
Warning!
G
Never lean over the battery while connect-
ing or jump starting.Warning!
G
Keep flames or sparks away from battery.
Do not smoke.
Observe all safety instructions and precau-
tions when handling automotive batteries
(page 232).
iThe vehicle cannot be started via
tow-start.

325 Practical hints
Towing the vehicle
Towing the vehicle
Mercedes-Benz recommends that the vehi-
cle be transported with all wheels off the
ground using flatbed or appropriate wheel
lift/dolly equipment.When circumstances do not permit the
recommended towing methods, the vehi-
cle may be towed with all wheels on the
ground or front wheels raised only so far as
necessary to have the vehicle moved to a
safe location where the recommended
towing methods can be employed.
!Use flatbed or wheel lift/dolly equip-
ment with key in starter switch turned
to position0.
Do not tow with sling-type equipment.
Towing with sling-type equipment over
bumpy roads will damage radiator and
supports.
To prevent damage during transport,
do not tie down vehicle by its chassis or
suspension parts.
Switch off the tow-away alarm and the
automatic central locking.
!If the vehicle is towed with the front
axle raised, the engine must be shut off
(key in starter switch position0 or1).
Otherwise, the ESP will immediately be
engaged and will apply the rear wheel
brakes.
When towing the vehicle with all wheels
on the ground, the selector lever must
be in positionN and the key must be in
starter switch position2.
When towing the vehicle with all wheels
on the ground or the front axle raised,
the vehicle may be towed only for dis-
tances up to 30 miles (50 km) and at a
speed not to exceed 30 mph (50
km/h).
!To be certain to avoid a possibility of
damage to the transmission, however,
we recommend the drive shaft be dis-
connected at the rear axle drive flange
for any towing beyond a short tow to a
nearby garage.

326 Practical hintsTowing the vehicleWarning!
G
If circumstances require towing the vehicle
with all wheels on the ground, always tow
with a tow bar if:

the engine will not run


there is a malfunction in the SBC brake
system


there is a malfunction in the power sup-
ply or in the vehicle’s electrical system
as that will be necessary to adequately con-
trol the towed vehicle.
Prior to towing the vehicle with all wheels on
the ground, make certain that the key is in
starter switch position2.
If the key is left in the starter switch
position0 for an extended period of time, it
can no longer be turned in the switch. In this
case, the steering is locked. To unlock, re-
move key from starter switch and reinsert.
iTo signal turns while being towed with
the hazard warning flasher in use, turn
key in starter switch to position2 and
activate the combination switch for the
left or right turn signal in the usual
manner – only the selected turn signal
will operate.
Upon canceling the turn signal, the haz-
ard warning flasher will operate again.
Warning!
G
The brake system requires electrical power
to operate.
A malfunction in the vehicle’s power supply
or electrical system may impair brake sys-
tem operation and switch it into its
limp-home (emergency operation) mode. To
brake, the driver must then apply signifi-
cantly greater brake pedal pressure and de-
press the pedal much further to obtain the
expected braking effect. If necessary, apply
full pressure to the brake pedal. Brakes are
only applied to the front wheels. Stopping
distance is increased! Adapt your driving
style accordingly. SBC brake system
(page 72).
With the engine not running, there is no
power assistance for the steering system. In
this case, it is important to keep in mind that
a considerably higher degree of effort is nec-
essary to steer the vehicle. Adapt your driv-
ing accordingly.

327 Practical hints
Towing the vehicle
Installing towing eye bolt
Front of vehicle
1Cover on right side of front bumper.
To remove cover:
Press mark on cover in direction of ar-
row.

Lift cover off to reveal threaded hole for
towing eye bolt.
!When towing the vehicle with all wheels
on the ground, please note the follow-
ing:
With the automatic central locking acti-
vated and the key in starter switch
position2, or KEYLESS-GO* start/stop
button (if so equipped) in position2,
the vehicle doors lock if the left front
wheel as well as the right rear wheel
are turning at vehicle speeds of approx.
9mph (15km/h) or more.
To prevent the vehicle door locks from
locking, deactivate the automatic cen-
tral locking (
page 91).
Towing of the vehicle should only be
done using the properly installed tow-
ing eye bolt. Never attach tow cable,
tow rope or tow rod to the vehicle chas-
sis, frame or suspension parts.
iThe selector lever will remain locked in
positionP and the key will not turn in
the starter switch if the battery is dis-
connected or discharged. See notes on
the battery (
page 319) or on jump
starting (
page 323).