Page 155 of 208

WARNING■When you charge a battery, hydrogen is released, and a highly explosive
gas mixture is also produced. An explosion can be caused through sparkling
over during unclamping or loosening of the cable plug while the ignition is
on.■
Creating a bridge between the poles on the battery (e.g. with metal ob-
jects - cables) creates a short circuit - risk of damage to the battery, explo-
sion and burning of the battery, jets of acid spurting out.
■
Avoid creating sparks when working with cables and electrical devices.
Strong sparking represents a risk of injury.
■
Before carrying out any work on the electrical system, switch off the en-
gine, the ignition and all electrical consumers and disconnect the negative
terminal
.
■
“Quick-charging” the vehicle battery is dangerous and requires a special
charger and specialist knowledge.
■
We therefore recommend that vehicle batteries be “rapidly charged” by a
specialist garage.
CAUTION
On vehicles with the START/STOP system, the pole terminal of the charger
must not be connected directly to the negative terminal of the vehicle battery,
but only to the engine earth » page 168, Jump-starting using the battery from
another vehicle .
Replacing
Read and observe
and on page 151 first.
The new vehicle battery must have the same capacity, voltage, current and
size as the original battery. Suitable vehicle battery types can be purchased
from a specialist garage.
We recommend you have the battery replaced by a specialist garage.
Disconnecting and reconnecting
Read and observe
and on page 151 first.
Disconnecting
›
Switch off the ignition.
›
First, disconnect the negative terminal
first, then the positive
terminal
of the battery.
Connecting›First, connect the positive first, then the negative battery terminal.
After disconnecting and re-connecting the vehicle battery, the following func-
tions or devices are partially or completely inoperative.Function / deviceCommissioningTime settings» page 31
CAUTION
■ Disconnect the vehicle battery only with the ignition turned off - there is a
risk of damaging the electrical system of the vehicle.■
Under no circumstances must the battery cables be connected incorrectly –
risk of a cable fire.
Note
■ After disconnecting and re-connecting the vehicle battery, we recommend
having the vehicle checked by a specialist to ensure that the full functionality
of all electrical systems is guaranteed.■
The data of the multi-function display will be reset.
Automatic load deactivation
Read and observe
and on page 151 first.
The vehicle's electrical system automatically prevents the battery from dis-
charging when the battery is being heavily used. This manifests itself by the
following. ▶ The idling speed is raised to allow the generator to deliver more electricity to
the electrical system.
▶ Where necessary, large convenience consumers such as seat heaters and
rear window heaters have their power limited or are shut off completely in
the event of an emergency.
CAUTION
■ Despite such intervention by the vehicle electric system management, the
vehicle battery may be drained. For example, when the ignition is switched on
a long time with the engine turned off or the side or parking lights are turned
on during longer parking.■
Consumers that are supplied via a 12-V power socket can cause the vehicle
battery to discharge when the ignition is switched off.
153Inspecting and replenishing
Page 178 of 208

No.Power consumer15Air conditioning system, selector lever of the automatic gearbox, di-
agnosis terminal16Instrument cluster17Alarm system, horn18Not assigned19Not assigned20Not assigned21Not assigned22Front- and rear windscreen wiper system23Heated front seats24Blower fan for air conditioning system, heating, air conditioning,
heating25Not assigned26Switch for front seat heating27Rear window wiper28Not assigned29airbag30Electric power windows, light switches, reverse light switches, air
conditioning system, Park Assist, exterior mirror, power feed for cen-
tre button strip, power feed for side button strip, interior mirror31Fuel pump, radiator fan, cruise control, coil of the relay for the front
and rear windscreen wipers32Diagnostic terminal, headlight range control, operating lever under
the steering wheel, interior lighting33Coil on starter relay, clutch pedal switch34Heated windscreen washer jets35Not assigned36Not assigned37Radar38Not assigned39Electrical auxiliary heating system40Not assigned41Rear window heaterNo.Power consumer42Power windows - front passenger43Towing hitch - contact in the socket44Cigarette lighter, 12-volt power socket45Power windows - rear right46Front and rear window washer, operating lever under the steering
wheel47Towing hitch - contact in the socket48Towing hitch - right light49Fuel pump50Radio51Heating of the external mirror52KESSY53Steering lock (KESSY)54ABS or ESC55Not assigned56Not assigned57Not assigned58Not assigned59Not assigned
Fuses in the engine compartment
Fig. 185
Cover for the fuse box - variant 1
176Do-it-yourself
Page 179 of 208

Fig. 186
Cover for the fuse box - variant 2
Read and observe
and on page 174 first.
Replacing fuses
›
Press the lock button on the cover in direction of arrow
1
» Fig. 185 or
» Fig. 186 .
›
Raise the cover and remove in the direction of the arrow
2
.
›
Remove the plastic clip from the holder in the fuse box cover.
›
Replace the appropriate fuse.
›
Replace the bracket at the original position.
›
Place the cover on top of the fuse box.
›
Push in the locking button on the cover and lock.
The cover must engage securely.
CAUTION
The cover for the fuse box in the engine compartment must always be re-
placed correctly. Water may get into the fuse box if the cover is not replaced
properly - there is a risk of damage to the vehicle!
Fuse assignment in the engine compartment
Fig. 187
Fuses
Read and observe and on page 174 first.No.Power consumer1Radiator fan2Glow plug system3ABS or ESC4Auxiliary electric heating - circuit 25Auxiliary electric heating - circuit 36Automatic gearbox7Engine control unit8Windscreen wipers9Central control unit, battery data module10ABS or ESC11Not assigned12Engine components13Brake pedal switch14Engine components, coil for the fuel pump relay, radiator fan, cooling
pump15Engine control unit16Starter17Engine control unit18Engine components, coils of the relay for auxiliary electric heater19Lambda probe20Glow plug system, crankcase ventilation heater
Replacing bulbs
Introduction
This chapter contains information on the following subjects:
Bulb arrangement in the headlights
178
Replacing the high beam bulb (halogen headlights)
179
Replacing bulb for main beam, daytime running lights and parking light
179
Changing the front turn signal bulb
180
Replacing the bulb for the fog light
180
177Fuses and light bulbs