Mercedes-Benz B-Class w242, w246 (2012 – present) – fuse box diagram
Year of production: 2012, 2013, 2014, 2015, 2016, 2017, 2018
Fuse box in the engine compartment
| No. | Fused function | A |
| 201 | Alarm siren | 5 |
| 202 | Stationary heater control unit | 20 |
| Electric Drive (W242): Park pawl control unit circuit 87 relay | 5 | |
| 203 | LED headlamp: Right front lamp unit | 15 |
| 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 relay87M |
5 |
| 207 | Valid for diesel engine: Circuit relay87M 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 |
| Electric Drive (W242): Fan motor | 5 | |
| 209 | LED headlamp: Left front lamp unit | 15 |
| Electric Drive (W242): Spare | – | |
| 210 | Heated windshield relay | 5 |
| as of 03.11.2014 except (Canada version): Starter front-end relay | 5 | |
| 211 | Natural Gas Drive (W242): CNG control unit | 7.5 |
| 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 |
| 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 Valid for engine 607: CDI control unit Boost pressure positioner Quantity control valve |
20 |
| Electric Drive (W242): Thermal management control unit Gateway powertrain control unit Electric Drive (W242) as of 03.11.2014: High-voltage power distributor |
5 | |
| 216 | Valid for gasoline engine: ME-SFI control unit Valid for engine 607: Powertrain control unit |
5 |
| 217 | Valid with transmission 724: Dual clutch transmission fully integrated transmission control unit | 25 |
| 218 | Electronic Stability Program control unit | 5 |
| 219 | Electric Drive (W242): Park pawl control unit | 5 |
| 220 | Transmission cooling coolant circulation pump | 10 |
| 221 | Electric Drive (W242): Vacuum pump | 40 |
| 222 | Electric Drive (W242): Electrical refrigerant compressor | 7.5 |
| 223 | Spare | – |
| 224 | DISTRONIC electric controller unit COLLISION PREVENTION ASSIST controller unit |
7.5 |
| 225 | Electric Drive (W242): Powertrain control unit | 5 |
| 226 | Natural Gas Drive (W242): CNG control unit Electric Drive (W242): Charger control unit Power electronics control unit |
5 |
| 227 | Electric Drive (W242): Power electronics control unit | 5 |
| 228 | Electric Drive (W242): Electric vehicle sound generator | 5 |
| 229 | Left front lamp unit | 5 |
| 230 | Electronic Stability Program control unit | 5 |
| 231 | Right front lamp unit | 5 |
| 232 | Headlamp control unit | 15 |
| 233 | Spare | – |
| 234 | Valid for engine 607: Powertrain control unit | 5 |
| Electric Drive (W242): High-voltage power distributor | 10 | |
| 235 | Valid for engine 607: Fan motor Radiator shutters actuator |
7.5 |
| Valid for engine 133: Charge air cooler circulation pump Charge air cooler circulation pump |
7.5 | |
| 236 | SAM control unit | 40 |
| 237 | Electronic Stability Program control unit | 40 |
| 238 | Heated windshield | 50 |
| 239 | Wiper speed 1/2 relay | 30 |
| 240A | Starter circuit 50 relay | 25 |
| Electric Drive (W242): Powertrain control unit | 7.5 | |
| 240B | Circuit 15 relay (not latched) | 25 |
| 241 | Electric Drive (W242): High-voltage PTC heater | 7.5 |
| Relay | ||
| J | Fanfare horn relay | |
| K | Wiper speed 1/2 relay | |
| L | Windshield wiper ON/OFF relay | |
| M | Starter circuit 50 relay Electric Drive (W242): Circuit 87C relay |
|
| N | Circuit relay87M | |
| O | ECO start/stop: Transmission cooling coolant circulation pump relay Electric Drive (W242): Park pawl control unit circuit 87 relay |
|
| P | Backup relay (F58kP) | |
| Q | Circuit 15 relay (not latched) Electric Drive (W242): Brake booster vacuum pump supply relay (F58kQ) |
|
| R | Circuit 15 relay | |
| S | Circuit 87 relay | |
| T | Heated windshield relay | |
Fuse box in the front-passenger foot-well
| No. | Fused function | A |
| 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 |
| 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 |
| 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 |
| Adaptive damping system control unit | 25 | |
| 48 | Spare | – |
| 49 | Control unit for Drive Kit for iPhone® | 7,5 |
| 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 |
| Special vehicle: Special-purpose vehicle multifunction control unit | 7.5 | |
| 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 |
| 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 |
| 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 |
| Electric Drive (W242): Battery management system control unit (N82/2) | 5 | |
| 76 | Trailer recognition control unit (N28/1) | 25 |
| 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 |
| Tuner unit | 7,5 | |
| 106 | Multifunction camera | 5 |
| 107 | Digital TV tuner | 5 |
| 108 | up to 31.05.2016: Reversing camera | 5 |
| 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 | |
Front electrical prefuse box
| No. | Fused function | A |
| 1 | Alternator | 300 |
| Electric Drive (W242): DC/DC converter control unit | 400 | |
| 2 | Vehicle interior fuse box | 200 |
| Valid for diesel engine: Vehicle interior fuse box | 250 | |
| 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 | ||
| F32k1 | Decoupling relay | |
WARNING: Terminal and harness assignments for individual connectors will vary depending on vehicle equipment level, model, and market.