Mercedes-Benz B-Class (W242/W246; 2012-2018) fuses and relays

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In this article, we consider the second-generation Mercedes-Benz B-Class (W242, W246), produced from 2011 to 2018. Here you will find fuse box diagrams of Mercedes-Benz B160, B180, B200, B220, B250 2012, 2013, 2014, 2015, 2016, 2017 and 2018, get information about the location of the fuse panels inside the car, and learn about the assignment of each fuse (fuse layout) and relay.

See other Mercedes-Benz B-Class:

Fuse Layout Mercedes-Benz B-Class 2012-2018

Cigar lighter (power outlet) fuses in the Mercedes-Benz B-Class are the fuses #70 (Rear center console socket), #71 (Luggage compartment socket) and #72 (Front cigarette lighter, interior power outlet) in the Passenger Compartment fuse box.

Table of Contents

Fuse box location

The fuse box is located under the floor near the passenger seat. Fold out perforated floor covering (1) in the direction of the arrow.
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).

Fuse box diagram

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Assignment of the fuses and relay in the passenger compartment

Fused function Amp
21 Valid for diesel engine: PTC heater booster 150
22 Additional battery relay for ECO start/stop function 200
23 Left front door control unit 30
24 Right front door control unit 30
25 SAM control unit 30
26 ECO start/stop additional battery connector sleeve 10
27 Engine compartment fuse and relay module 30
28 Vehicle interior sound generator control unit
Electric Drive (W242): Thermal management control unit
5
29 up to 02.11.2014: Trailer socket
as of 03.11.2014: Trailer recognition control unit
15
30 Trailer recognition control unit 5
31 4MATIC: All-wheel drive control unit 5
32 Steering column tube module control unit 5
33 Audio/COMAND control panel 5
34 ACC control and operating unit 7,5
35 Rear window heater 40
36 Driver seat control unit
Driver seat lumbar support adjustment control unit
7,5
37 Audio/COMAND display 7,5
38 Supplemental Restraint System control unit 7,5
39 Overhead control panel control unit 10
40 Valid for engine 651 (Emissions standard EU6): Powertrain control unit 15
40 Electric Drive (W242): Powertrain control unit 5
41 Panoramic sliding sunroof control module 30
42 Radio (Audio 5 USB, Audio 20 CD, Audio 20 CD with CD changer)
COMAND controller unit
5
42 Radio (Radio 20, Audio 20 USB) 25
43 Parking system control unit 5
44 Left front reversible emergency tensioning retractor 40
45 Right front reversible emergency tensioning retractor 40
46 Front passenger seat control unit
Front passenger seat lumbar support adjustment control unit
7,5
47 Navigation module 7,5
47 Adaptive damping system control unit 25
48 Spare
49 Control unit for Drive Kit for iPhone® 7,5
49 COMAND fan motor 5
50 Spare
51 Spare
52 Electric Drive (W242): Park pawl actuator motor 30
53 Spare
54 Spare
55 Telematics services communications module
KEYLESS-GO control unit
5
56 Steering column tube module control unit 10
57 Lane Keeping Assist: Special-purpose vehicle multifunction control unit 30
57 Special vehicle: Special-purpose vehicle multifunction control unit 7.5
57 Electric Drive (W242): Park pawl actuator motor circuit 87 relay (F34kG) 5
58 Emergency vehicle fuse box 30
59 Front passenger seat control uni 30
60 Driver seat control unit 30
61 Sound system amplifier control unit 40
62 Valid for transmission 711: Electric steering lock control unit 20
63 Fuel system control unit 25
63 Electric Drive (W242): Gateway powertrain control unit 5
64 Electronic Toll Collection control unit
Dedicated Short-Range Communications control unit
1
65 Glove compartment lamp 5
66 Emergency vehicle fuse box 15
66 Special-purpose vehicle interface 5
67 Spare
68 Spare
69 Spare
70 Rear center console socket 25
71 Luggage compartment socket 25
72 Front cigarette lighter with ashtray illumination
Vehicle interior power outlet
25
73 Electric parking brake control unit 30
74 Electric parking brake control unit 30
75 Trailer recognition control unit 20
75 Electric Drive (W242): Battery management system control unit (N82/2) 5
76 Trailer recognition control unit (N28/1) 25
76 Electric Drive (W242): Park pawl control unit 5
77 Trailer recognition control unit 25
78 Emergency vehicle fuse box 40
79 SAM control unit 40
80 SAM control unit 40
81 Blower regulator 40
82 Overhead control panel control unit 10
83 Electronic ignition lock control unit 7,5
84 Upper control panel control unit 5
85 ATA [EDW]/tow-away protection/interior protection control unit 5
86 FM, AM and CL [ZV] antenna amplifier
as of 01.06.2016: Cellular telephone system antenna amplifier / compensator
5
87 Diagnostic connector 10
88 Instrument cluster 10
89 Exterior lights switch 5
90 Left rear bumper intelligent radar sensor
Intelligent radar sensor for right rear bumper
5
91 Pedal operation monitor switch
Footwell illumination switch
Electric Drive (W242): Battery management system control unit
5
92 Fuel system control unit
Electric Drive (W242): Gateway powertrain control unit
5
93 Electric parking brake control unit 5
94 Supplemental Restraint System control unit 7,5
95 Front passenger seat occupied recognition and ACSR
Weight sensing system (WSS) control unit
7,5
96 Tailgate wiper motor 15
97 Mobile phone electrical connector 5
98 SAM control unit 5
99 Tire pressure monitor control unit 5
100 Valid for engine 133: DIRECT SELECT INTERFACE 5
101 4MATIC: All-wheel drive control unit 10
102 Stationary heater radio remote control receiver

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

5
103 Emergency call system control unit
Telematics services communications module
HERMES control unit
5
104 Media interface control unit
Multimedia connection unit
5
105 Digital Audio Broadcasting control unit
Satellite digital audio radio (SDAR) control unit
5
105 Tuner unit 7,5
106 Multifunction camera 5
107 Digital TV tuner 5
108 up to 31.05.2016: Reversing camera 5
108 as of 01.06.2016: Reversing camera 7,5
109 Charging socket electrical connector 20
110 Radio
COMAND controller unit
Engine sound control unit
30
Relay
A Circuit 15 relay
B Rear window wiper relay
C Circuit 15R2 relay
D Heated rear window relay
E Circuit 15R1 relay
F Circuit 30g relay
G Electric Drive (W242): Park pawl actuator motor circuit 87 relay

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Front Electrical Prefuse Box

Fused function Amp
1 Alternator 300
1 Electric Drive (W242): DC/DC converter control unit 400
2 Vehicle interior fuse box 200(petrol)
250(diesel)
3 Electrical power steering control unit 100
4 SAM control unit 40
5 Fan motor 80
6 Valid for engine 607: Fuel preheating control unit 70
7 Valid for engine 607 (Emissions standard EU5): DPF regeneration heater booster control unit 125
8 Valid for engine 607, 651: Glow output stage 100
Relay
F32kl Decoupling relay

Fuse box location

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Fuse box diagram

Assignment of the fuses and relay in the engine compartment

Fused function Amp
201 Alarm siren 5
202 Stationary heater control unit 20
202 Electric Drive (W242): Park pawl control unit circuit 87 relay 5
203 LED headlamp: Right front lamp unit 15
203 Electric Drive (W242): Powertrain control unit 5
204 Electronic Stability Program control unit 25
205 Left fanfare horn
Right fanfare horn
15
206 Valid for engine 651: CDI control unit
Valid for engine 607: Powertrain control unit
Electric Drive (W242): Brake booster vacuum pump relay Circuit relay 87M
5
207 Valid for diesel engine: Circuit relay 87M
Electric Drive (W242): High-voltage battery cooling shutoff valve Park pawl control unit
5
208 Valid for engine 133, 607: Circuit 87 relay 7.5
208 Electric Drive (W242): Fan motor 5
209 LED headlamp: Left front lamp unit 15
209 Electric Drive (W242): Spare
210 Heated windshield relay 5
210 as of 03.11.2014 except (Canada version): Starter front-end relay 5
211 Natural Gas Drive (W242): CNG control unit 7.5
211 Electric Drive (W242): Heater circuit circulation pump 15
212 Valid for engine 133, 270: Connector sleeve, circuit 87M3

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

15
213 Valid for engine 133, 270, 651: Connector sleeve, circuit 87 M2e

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

15
214 Valid for engine 133, 270, 651: Connector sleeve, circuit 87 M4e 10
214 Electric Drive (W242): Battery cooling system coolant pump 2 15
215 Valid for gasoline engine:
Cylinder 1 ignition coil
Cylinder 2 ignition coil
Cylinder 3 ignition coil
Cylinder 4 ignition coil

Valid for engine 651: Quantity control valve