Page 335 of 417
334 Practical hints
Replacing SmartKey batteries
SmartKey
Replacement batteries: Lithium, type 
CR 2025 or equivalent.
Remove mechanical key (page 327).
1Mechanical key
2Slide
3Battery compartment
Insert mechanical key1 in direction 
of arrow in side opening.
Using mechanical key1, push gray 
slide2 to unlatch battery 
compartment3.
Pull battery compartment3 out of the 
housing in direction of arrow.
Remove the discharged batteries in di-
rection of arrow.
4Battery
5Contact spring
Using a lint-free cloth, insert new 
batteries4 under contact spring5 
with the positive terminal (+) facing up.
Return battery compartment2 into 
the housing until it locks into place.
Slide mechanical key1 back into the 
SmartKey.
Check the operation of the SmartKey. 
     
        
        Page 354 of 417

353 Practical hints
Battery
Battery
The battery is located in front of the rear 
seat bench and below the cup holder
Batteries contain materials that can harm 
the environment if disposed of improperly. 
Large 12 volt storage batteries contain 
lead. 
Recycling of batteries is the preferred 
method of disposal. Many states require 
sellers of batteries to accept old batteries 
for recycling.Charging the battery
Warning!G
Failure to follow these instructions can re-
sult in severe injury or death.
Observe all safety instructions and precau-
tions when handling automotive batteries 
(
page 251).
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.
Warning!G
Do not place metal objects on the battery as 
this could result in a short circuit. 
Use leak-proof battery only to avoid the risk 
of acid burns in the event of an accident.Warning!G
Never charge a battery while still installed in 
the vehicle unless the accessory battery 
charge unit* approved by Mercedes-Benz is 
being used. Gases may escape during charg-
ing and cause explosions that may result in 
paint damage, corrosion or personal injury.
An accessory battery charge unit* specially 
adapted for Mercedes-Benz vehicles and 
tested and approved by Mercedes-Benz is 
available, permitting the charging of the bat-
tery in its installed position. Contact an 
authorized Mercedes-Benz Light Truck 
Center for information and availability. 
Charge battery in accordance with the sepa-
rate instructions for the accessory battery 
charger*. 
     
        
        Page 355 of 417

354 Practical hints
Battery
Have the battery removed at a 
Mercedes-Benz Light Truck Center.
If you charge the battery yourself, make 
sure to comply with the operating instruc-
tions for your battery charger.Disconnecting the battery
Read and observe safety instructions 
and precautions (
page 251) and 
(
page 353).
Turn off all electrical consumers.
Disconnect the battery negative lead.
Remove the cover from the positive ter-
minal.
Disconnect the battery positive lead.
Remove the breather hose from the 
battery.
!
Have the battery checked regularly by 
an authorized Mercedes-Benz Light 
Truck Center. 
Refer to Maintenance Booklet for main-
tenance intervals or contact an autho-
rized Mercedes-Benz Light Truck 
Center for further information.
!
Never loosen or detach battery termi-
nal clamps while the engine is running 
or the SmartKey is in the starter switch. 
Otherwise the alternator and other 
electronic components could be se-
verely damaged.
Warning!G
With a disconnected battery
you will no longer be able to turn the 
SmartKey in the starter switch
the gear selector lever will remain 
locked in position
P 
     
        
        Page 356 of 417
355 Practical hints
Battery
Reconnecting the battery
Turn off all electrical consumers.
Connect the positive lead and fasten its 
cover.
Connect the negative lead.
Install the breather hose.
!
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.
i
The following procedures must be car-
ried out following any interruption of 
battery power (e.g. due to reconnec-
tion):
Set the clock (see COMAND 
operator’s manual).
Resynchronize the front seat head 
restraints and seat adjustment fore, 
aft (
page 102).
Synchronize the ESP (page 302). 
     
        
        Page 357 of 417

356 Practical hints
Jump starting
If the battery is discharged, the engine can 
be started with jumper cables and the bat-
tery 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 12 volt battery 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.
Use only jumper cables with sufficient 
cross-section and insulated terminal 
clamps.
Always make sure the jumper cables 
are not on or near pulleys, fans, or 
other parts that move when an 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.
Attempting to jump start a frozen battery 
can result in it exploding, causing personal 
injury.
Read all instructions before proceeding.
!
Avoid repeated and lengthy starting at-
tempts.
Do not attempt to start the engine us-
ing a battery quick charge unit.
If engine does not run after several un-
successful starting attempts, have it 
checked at the nearest authorized 
Mercedes-Benz Light Truck 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.
!
Do not tow-start the vehicle. 
     
        
        Page 358 of 417

357 Practical hints
Jump starting
The jump-start contacts are located in the 
engine compartment.
Make sure the two vehicles do not 
touch.
Turn off all electrical consumers.
Apply parking brake.
Shift gear selector lever to positionP.1Cover
2Positive (+) terminal 
3Negative (-) terminal 
Open cover1 of the positive terminal 
of both vehicles. 
Connect the positive terminal2 and 
the positive terminal of the charged 
battery with the jumper cable. Clamp 
cable to charged battery first.
Start engine of the vehicle with the 
charged battery and run at idle speed.
Connect negative terminal3 and the 
negative terminal of the charged bat-
tery with the jumper cable. Clamp ca-
ble to charged battery first.
Start the engine of the disabled 
vehicle.
Now you can again turn on the electrical 
consumers. Do not turn on the lights under 
any circumstances.
Remove the jumper cables first from 
the negative terminals on each battery 
and then from the positive terminals on 
each battery.
You can now turn on the lights.
Have the battery checked at the 
nearest authorized Mercedes-Benz 
Light Truck Center.
Warning!G
Keep flames or sparks away from battery. 
Do not smoke. 
Observe all safety instructions and precau-
tions when handling automotive batteries 
(
page 251) and (page 353). 
     
        
        Page 360 of 417

359 Practical hints
Towing the vehicle
Warning!G
With the engine not running, there is no 
power assistance for the brake and steering 
systems. In this case, it is important to keep 
in mind that a considerably higher degree of 
effort is necessary to brake and steer the ve-
hicle. Adapt your driving accordingly.
i
The gear selector lever will remain 
locked in positionP and the SmartKey 
will not turn in the starter switch if the 
battery is disconnected or discharged. 
For more information, see “Battery” 
(
page 353) and “Jump starting” 
(
page 356).
For information on manually unlocking 
transmission gear selector lever, see 
(
page 329).
i
To signal turns while being towed with 
hazard warning flasher in use, turn 
SmartKey in starter switch to 
position2 and activate combination 
switch for left or right turn signal in 
usual manner – only the selected turn 
signal will operate.
Upon canceling the turn signal, the 
hazard warning flasher will operate 
again.
!
When towing the vehicle with all wheels 
on the ground, note the following:
With the automatic central locking acti-
vated and the SmartKey in starter 
switch position2, the vehicle doors 
lock if the wheels are turning at vehicle 
speeds of approx. 9 mph (15 km/h) or 
more.
To prevent the vehicle doors from lock-
ing, deactivate the automatic central 
locking (
page 142).
Towing of the vehicle should only be 
done using the towing eye. Never at-
tach tow cable, tow rope or tow rod to 
vehicle chassis, frame or suspension 
parts. 
     
        
        Page 363 of 417
362 Practical hints
Fuses
The fuse box is located on the left side of 
the cockpit in the passenger compart-
ment. It contains:
Fuse chart
Spare fuses
Special spare extractor
Additional fuses are located in:
Battery box
Front passenger footwell under the 
cockpit
Middle tunnel
Fuse box in passenger compartment
Opening
1Cover
Open the driver’s door.
Remove cover1 in direction of ar-
rows.
Fuse box in battery box
The battery box is located under the cover 
in the rear footwell.
Replacement of fuses can only be per-
formed by a Mercedes-Benz Light Truck 
Center.i
Only install fuses that have been tested 
and approved by Mercedes-Benz and 
that have the specified amperage rat-
ing.
Never attempt to repair or bridge a 
blown fuse. Have the cause determined 
and remedied by an authorized 
Mercedes-Benz Light Truck Center.
!
Do not use sharp objects such as a 
screw driver to open fuse box cover1 
in the dashboard, as this could damage 
it.