Mercedes-Benz B-Class (W246, W242) (2011-2018) Fuse Diagram

Fuse box diagram (fuse layout), location, and assignment of fuses and relays Mercedes-Benz B-Class B160, B180, B200, B220, B250 and Electric Drive (W246, W242) (2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018.

Mercedes-Benz B-Class (W246, W242) (2011-2018)

Checking and Replacing Fuses

The fuses in your vehicle serve to close down faulty circuits. If a fuse blows, all the components on the circuit and their functions stop operating. If a fuse has blown, the inside element will be melted. Blown fuses must be replaced with fuses of the same rating, which you can recognize by the color and value. The fuse ratings are listed in the fuse allocation chart (It is on the fuse box in the front-passenger footwell).

If a newly inserted fuse also blows, have the cause traced and rectified at a qualified specialist workshop, e.g. an authorized Mercedes-Benz Center.

Notice

  • Before changing a fuse, secure the vehicle against rolling away and switch off all electrical consumers.
  • Always disconnect the battery before servicing high current fuses.
  • Always replace faulty fuses with the specified new fuses having the correct amperage. If you manipulate or bridge a faulty fuse or if you replace it with a fuse with a higher amperage, the electric cables could be overloaded. This could result in a fire. There is a risk of an accident and injury.
  • Only use fuses that have been approved for Mercedes-Benz vehicles and which have the correct fuse rating for the system concerned. Only use fuses marked with an “S”. Otherwise, components or systems could be damaged.

Passenger Compartment Fuse Box

The fuse box is located in the front-passenger foot-well.

Passenger Compartment Fuse Box Location

  • To open: open the front-passenger door.
  • Remove the floormat.
  • Fold-out perforated floor covering (1) in the direction of the arrow.

Passenger Compartment Fuse Box Location

  • To release cover (3), press retaining clamp (2).
  • Fold-out cover (3) in the direction of the arrow to the catch.
  • Remove cover (3) forwards.
    Fuse allocation chart (4) is located on the lower right-hand side of the cover (3).
  • To close: insert cover (3) on the left-hand side of the fuse box into the retainer. Cover (3) engages in the retainers.
  • Fold-down cover (3) until clamps (2) lock audibly.
  • Fold back the perforated floor covering (1).
  • Install the floormats.

Passenger Compartment Fuse Box Diagram

Fused functionA
21Valid for diesel engine: PTC heater booster150
22Additional battery relay for ECO start/stop function200
23Left front door control unit30
24Right front door control unit30
25SAM control unit30
26ECO start/stop additional battery connector sleeve10
27Engine compartment fuse and relay module30
28Vehicle interior sound generator control unit5
Electric Drive (W242): Thermal management control unit
29up to 02.11.2014: Trailer socket15
as of 03.11.2014: Trailer recognition control unit
30Trailer recognition control unit5
314MATIC: All-wheel drive control unit5
32Steering column tube module control unit5
33Audio/COMAND control panel5
34ACC control and operating unit7.5
35Rear window heater40
36Driver seat control unit7.5
Driver seat lumbar support adjustment control unit
37Audio/COMAND display7.5
38Supplemental Restraint System control unit7.5
39Overhead control panel control unit10
40Valid for engine 651 (Emissions standard EU6): Powertrain control unit15
Electric Drive (W242): Powertrain control unit5
41Panoramic sliding sunroof control module30
42Radio (Audio 5 USB, Audio 20 CD, Audio 20 CD with CD changer)5
COMAND controller unit
Radio (Radio 20, Audio 20 USB)25
43Parking system control unit5
44Left front reversible emergency tensioning retractor40
45Right front reversible emergency tensioning retractor40
46Front passenger seat control unit7.5
Front passenger seat lumbar support adjustment control unit
47Navigation module7.5
Adaptive damping system control unit25
48Spare-
49Control unit for Drive Kit for iPhone®7.5
COMAND fan motor5
50Spare-
51Spare-
52Electric Drive (W242): Park pawl actuator motor30
53Spare-
54Spare-
55Telematics services communications module5
KEYLESS-GO control unit
56Steering column tube module control unit10
57Lane Keeping Assist: Special-purpose vehicle multifunction control unit30
Special vehicle: Special-purpose vehicle multifunction control unit7.5
Electric Drive (W242): Park pawl actuator motor circuit 87 relay (F34kG)5
58Emergency vehicle fuse box30
59Front passenger seat control uni30
60Driver seat control unit30
61Sound system amplifier control unit40
62Valid for transmission 711: Electric steering lock control unit20
63Fuel system control unit25
Electric Drive (W242): Gateway powertrain control unit5
64Electronic Toll Collection control unit1
Dedicated Short-Range Communications control unit
65Glove compartment lamp5
66Emergency vehicle fuse box15
Special-purpose vehicle interface5
67Spare-
68Spare-
69Spare-
70Rear center console socket25
71Luggage compartment socket25
72Front cigarette lighter with ashtray illumination25
Vehicle interior power outlet 
73Electric parking brake control unit30
74Electric parking brake control unit30
75Trailer recognition control unit20
Electric Drive (W242): Battery management system control unit (N82/2)5
76Trailer recognition control unit (N28/1)25
Electric Drive (W242): Park pawl control unit5
77Trailer recognition control unit25
78Emergency vehicle fuse box40
79SAM control unit40
80SAM control unit40
81Blower regulator40
82Overhead control panel control unit10
83Electronic ignition lock control unit7.5
84Upper control panel control unit5
85ATA [EDW]/tow-away protection/interior protection control unit5
86FM, AM and CL [ZV] antenna amplifier5
as of 01.06.2016: Cellular telephone system antenna amplifier / compensator
87Diagnostic connector10
88Instrument cluster10
89Exterior lights switch5
90Left rear bumper intelligent radar sensor5
Intelligent radar sensor for right rear bumper
91Pedal operation monitor switch5
Footwell illumination switch
Electric Drive (W242): Battery management system control unit
92Fuel system control unit5
Electric Drive (W242): Gateway powertrain control unit
93Electric parking brake control unit5
94Supplemental Restraint System control unit7.5
95Front passenger seat occupied recognition and ACSR7.5
Weight sensing system (WSS) control unit
96Tailgate wiper motor15
97Mobile phone electrical connector5
98SAM control unit5
99Tire pressure monitor control unit5
100Valid for engine 133: DIRECT SELECT INTERFACE5
1014MATIC: All-wheel drive control unit10
102Stationary heater radio remote control receiver5
Electric Drive (W242): Powertrain control unit
Valid for AMG vehicles as of 01.09.2015: Transmission mode control unit
as of 01.06.2016: Antenna changeover switch for telephone and stationary heater
103Emergency call system control unit5
Telematics services communications module
HERMES control unit
104Media interface control unit5
Multimedia connection unit
105Digital Audio Broadcasting control unit5
Satellite digital audio radio (SDAR) control unit
Tuner unit7.5
106Multifunction camera5
107Digital TV tuner5
108up to 31.05.2016: Reversing camera5
as of 01.06.2016: Reversing camera5
109Charging socket electrical connector20
110Radio30
COMAND controller unit
Engine sound control unit
Relay
ACircuit 15 relay
BRear window wiper relay
CCircuit 15R2 relay
DHeated rear window relay
ECircuit 15R1 relay
FCircuit 30g relay
GElectric Drive (W242): Park pawl actuator motor circuit 87 relay

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Engine Compartment Fuse Box

Engine Compartment Fuse Box Location

  • Open the hood.
  • Use a dry cloth to remove any moisture from the fuse box.
  • To open: unclip hood release cable (4) from bracket (3).
  • Open retaining clamps (2).
  • Fold cover (1) up in the direction of the arrow and remove it.

Engine Compartment Fuse Box Location

  • To close: check whether the seal is seated correctly in cover (1).
  • Insert cover (1) at the back into openings (5) on the fuse box.
  • Slide hood release cable (4) to the side and hold if necessary.
  • Fold-down cover (1).
  • Clip hood release cable (4) into bracket (3).

Engine Compartment Fuse Box Diagram

Fused functionA
201Alarm siren5
202Stationary heater control unit20
Electric Drive (W242): Park pawl control unit circuit 87 relay5
203LED headlamp: Right front lamp unit15
Electric Drive (W242): Powertrain control unit5
204Electronic Stability Program control unit25
205Left fanfare horn15
Right fanfare horn
206Valid for engine 651: CDI control unit5
Valid for engine 607: Powertrain control unit
Electric Drive (W242):
   Brake booster vacuum pump relay
   Circuit relay87M
207Valid for diesel engine: Circuit relay87M5
Electric Drive (W242):
   High-voltage battery cooling shutoff valve
   Park pawl control unit
208Valid for engine 133, 607: Circuit 87 relay7.5
Electric Drive (W242): Fan motor5
209LED headlamp: Left front lamp unit15
Electric Drive (W242): Spare-
210Heated windshield relay5
as of 03.11.2014 except (Canada version): Starter front-end relay5
211Natural Gas Drive (W242): CNG control unit7.5
Electric Drive (W242): Heater circuit circulation pump15
212Valid for engine 133, 270: Connector sleeve, circuit 87M315
Valid for engine 651:
   Vent line heater element
   Coolant thermostat heating element
   Exhaust gas recirculation cooler bypass switchover valve
Valid for engine 607 (Emissions standard EU5):
   Oxygen sensor upstream of catalytic converter
   Boost pressure positioner
Valid for engine 607 (Emissions standard EU6): Oxygen sensor upstream of catalytic converter
Valid for engine 607: CDI control unit
Electric Drive (W242): Electric drive and charger coolant pump
213Valid for engine 133, 270, 651: Connector sleeve, circuit 87 M2e15
Valid for engine 607 (Emissions standard EU5):
   Camshaft Hall sensor
   CDI control unit
   Quantity control valve
Valid for engine 607 (Emissions standard EU6):
   Oxygen sensor downstream of catalytic converter
   CDI control unit
Electric Drive (W242): Battery cooling system coolant pump 1
214Valid for engine 133, 270, 651: Connector sleeve, circuit 87 M4e10
Electric Drive (W242): Battery cooling system coolant pump 215
215Valid for gasoline engine:20
   Cylinder 1 ignition coil
   Cylinder 2 ignition coil
   Cylinder 3 ignition coil
   Cylinder 4 ignition coil
Valid for engine 651: Quantity control valve
Valid for engine 607:
   CDI control unit
   Boost pressure positioner
   Quantity control valve
Electric Drive (W242):5
   Thermal management control unit
   Gateway powertrain control unit
Electric Drive (W242) as of 03.11.2014: High-voltage power distributor
216Valid for gasoline engine: ME-SFI control unit5
Valid for engine 607: Powertrain control unit
217Valid with transmission 724: Dual clutch transmission fully integrated transmission control unit25
218Electronic Stability Program control unit5
219Electric Drive (W242): Park pawl control unit5
220Transmission cooling coolant circulation pump10
221Electric Drive (W242): Vacuum pump40
222Electric Drive (W242): Electrical refrigerant compressor7.5
223Spare-
224DISTRONIC electric controller unit7.5
COLLISION PREVENTION ASSIST controller unit
225Electric Drive (W242): Powertrain control unit5
226Natural Gas Drive (W242): CNG control unit5
Electric Drive (W242):
   Charger control unit
   Power electronics control unit
227Electric Drive (W242): Power electronics control unit5
228Electric Drive (W242): Electric vehicle sound generator5
229Left front lamp unit5
230Electronic Stability Program control unit5
231Right front lamp unit5
232Headlamp control unit15
233Spare-
234Valid for engine 607: Powertrain control unit5
Electric Drive (W242): High-voltage power distributor10
235Valid for engine 607:7.5
   Fan motor
   Radiator shutters actuator
Valid for engine 133:7.5
   Charge air cooler circulation pump
   Charge air cooler circulation pump
236SAM control unit40
237Electronic Stability Program control unit40
238Heated windshield50
239Wiper speed 1/2 relay30
240AStarter circuit 50 relay25
Electric Drive (W242): Powertrain control unit7.5
240BCircuit 15 relay (not latched)25
241Electric Drive (W242): High-voltage PTC heater7.5
Relay
JFanfare horn relay
KWiper speed 1/2 relay
LWindshield wiper ON/OFF relay
MStarter circuit 50 relay
Electric Drive (W242): Circuit 87C relay  
NCircuit relay87M
OECO start/stop: Transmission cooling coolant circulation pump relay
Electric Drive (W242): Park pawl control unit circuit 87 relay
PBackup relay (F58kP)
QCircuit 15 relay (not latched)
Electric Drive (W242): Brake booster vacuum pump supply relay (F58kQ)
RCircuit 15 relay
SCircuit 87 relay
THeated windshield relay

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Front electrical prefuse box

Front electrical prefuse box

Front electrical prefuse box

Fused functionA
1Alternator300
Electric Drive (W242): DC/DC converter control unit400
2Vehicle interior fuse box200
Valid for diesel engine: Vehicle interior fuse box250
3Electrical power steering control unit100
4SAM control unit40
5Fan motor80
6Valid for engine 607: Fuel preheating control unit70
7Valid for engine 607 (Emissions standard EU5): DPF regeneration heater booster control unit125
8Valid for engine 607, 651: Glow output stage100
Relay
F32k1Decoupling relay