Mercedes W246 (w242) is a series of B-class compact cars of the Mercedes-Benz brand, which was produced in 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019 with the designation B160,2 B2 . During this time, the model has undergone restyling. In our article you will find a description of the fuses and relays of the Mercedes w246 with block diagrams, photo examples of execution and locations. We will separately highlight the cigarette lighter fuses.
The purpose of fuses and relays may differ from that presented and depends on the year of manufacture and equipment level of your vehicle.
Cabin block
In the cabin, the main unit with fuses and relays is located under the panel, on the passenger side under a protective cover.
Description
| 21 | 150A Additional electric heater (vehicles with diesel engine) |
| 22 | 200A Auxiliary battery relay ECO Start-Stop function |
| 23 | 30A Front left door control unit |
| 24 | 30A Front right door control unit |
| 25 | 30A SAM control unit |
| 26 | 10A End cable coupling of the additional battery of the “ECO Start-Stop” function |
| 27 | 30A Engine compartment fuse and relay module |
| 28 | 5A Electric Drive (W242): Thermal control unit |
| 29 | 15A Trailer socket (until 02.11.2014) |
| Trailer detection control unit (from 03.11.2014) | |
| 30 | 5A Trailer detection control unit |
| 31 | 5A All-wheel drive control unit |
| 32 | 5A Signals from the steering column electronic module control unit |
| 33 | 5A Audio module/COMAND system control panel |
| 34 | 7.5A Climate control system control panel |
| 35 | 40A Heated rear window |
| 36 | 7.5A Driver’s seat control unit |
| Driver’s seat lumbar support adjustment control unit | |
| 37 | 7.5A Audio module/COMAND system display |
| 38 | 7.5A Passenger restraint system control unit (Supplemental Restraint System) |
| 39 | 10A Ceiling control panel |
| 40 | 15A Transmission control unit (engine 651) |
| 5A Electric Drive (W242): Transmission control unit | |
| 41 | 30A Panoramic sliding sunroof control module |
| 42 | 5A Audio Module |
| COMAND control module | |
| 25A Audio module | |
| 43 | 5A Parking assistance system control unit |
| 44 | 40A Reversible front left seat belt tensioner |
| 45 | 40A Reversible front right seat belt tensioner |
| 46 | 7.5A Front passenger seat control unit |
| Lumbar support adjustment control unit for the front passenger seat | |
| 47 | 7.5A Navigation module |
| 25A Adaptive damping system control unit | |
| 48 | Reserve |
| 49 | 7.5A Drive Kit Control Unit for iPhone |
| 5A COMAND fan motor | |
| 50 | 5A Camera cover control unit |
| 51 | Reserve |
| 52 | 30A Parking lock actuator motor signal |
| 53 | Reserve |
| 54 | Reserve |
| 55 | 5A Telecommunications Services Communication Module |
| KEYLESS-GO control unit | |
| 56 | 10A Signals from the steering column electronic module control unit |
| 57 | 30A Multifunctional control unit for special vehicle |
| 7.5A Multifunctional control unit for special vehicle | |
| 5A Relay terminal 87 parking lock actuator motor | |
| 58 | 30A Special Purpose Vehicle Fuse Block |
| 59 | 30A Front passenger seat control unit |
| 60 | 30A Driver seat control unit |
| 61 | 40A Speaker amplifier control unit |
| 62 | 20A Electric steering lock control unit (711 transmission) |
| 63 | 25A Fuel pump control unit |
| 5A Electric Drive (W242): Transmission interface control unit | |
| 64 | Electronic Toll Collection control unit |
| DSRC toll data transmission control unit | |
| 65 | 5A Glove box light bulb |
| 66 | 15A Special Purpose Vehicle Fuse Block |
| 5A Special vehicle interface | |
| 67 | Reserve |
| 68 | Reserve |
| 69 | Reserve |
| 70 | 25A Center console socket in the rear of the cabin |
| 71 | 25A Socket in the trunk |
| 72 | 25A Cigarette lighter with ashtray illumination at the front |
| Socket in the cabin | |
| 73 | 30A Electric parking brake control unit |
| 74 | 30A Electric parking brake control unit |
| 75 | 20A Trailer recognition system control unit |
| 5A Electric Drive (W242): Battery management system control unit | |
| 76 | 25A Trailer recognition system control unit |
| 5A Electric Drive (W242): Parking lock control unit | |
| 77 | 25A Trailer recognition system control unit |
| 78 | 40A Trunk lid control unit/tailgate drive control |
| Special purpose vehicle fuse block | |
| 79 | 40A SAM control unit |
| 80 | 40A SAM control unit |
| 81 | 40A Fan Controller |
| 82 | 10A Ceiling control panel |
| 83 | 7.5A Electronic ignition lock control unit |
| 84 | 5A Top control panel |
| 85 | 5A EDW/towing protection/interior security system control unit |
| 86 | 5A Antenna amplifier FM, AM and ZV |
| Mobile antenna amplifier/compensator (from 01.06.2016) | |
| 87 | 10A Diagnostic connector |
| 88 | 10A Instrument cluster |
| 89 | 5A Outdoor lighting switch |
| 90 | 5A Intelligent radar sensor in the rear bumper on the left |
| Intelligent radar sensor in the rear bumper on the right | |
| 91 | 5A Pedal pressure control sensor |
| Footwell lighting switch | |
| Electric Drive (W242): Battery management system control unit | |
| 92 | 5A Fuel pump control unit |
| Electric Drive (W242): Transmission interface control unit | |
| 93 | 5A Electric parking brake control unit |
| 94 | 7.5A Passenger restraint system control unit (Supplemental Restraint System) |
| 95 | 7.5A Occupancy recognition system and AKSE front passenger seat |
| Weight Sensing System control unit | |
| 96 | 15A Tailgate wiper motor |
| 97 | 5A Mobile phone electrical plug connection |
| 98 | 5A SAM control unit |
| 99 | 5A Tire pressure monitoring system control unit |
| 100 | 5A DIRECT SELECT interface (engine 133) |
| 101 | 10A All-wheel drive control unit |
| 102 | 5A Remote control receiver for autonomous heater |
| Transmission control unit (Electric Drive (W242)) | |
| Driving mode control unit (AMG, from 01.09.2015) | |
| Antenna switch for telephone and autonomous heater (from 01.06.2016) | |
| 103 | 5A Emergency call control unit |
| Telecommunications services communication module | |
| HERMES control unit | |
| 104 | 5A Multimedia interface control unit |
| Multimedia device connection module | |
| 105 | 5A Digital audio broadcasting control unit |
| Satellite Digital Audio Radio (SDAR) control unit | |
| 7.5A Tuner Module | |
| 106 | 5A Multifunctional Camera |
| 107 | 5A Digital TV Tuner |
| 108 | 5A Rear view camera |
| 7.5A Rear view camera (from 01.06.2016) | |
| 109 | 20A Electrical Plug Connection Socket for Cargo |
| 110 | 30A Audio module |
| COMAND control module | |
| Motorsound control unit | |
| Relay | |
| A | Relay terminals 15 |
| B | Rear window wiper relay |
| C | Relay terminals 15R2 |
| D | Rear window heating relay |
| AND | Relay terminal 15R1 |
| F | Relay terminals 30g |
| G | Electric Drive (W242): Relay terminal 87 parking lock actuator motor |
Fuses 70, 71, and 72 are responsible for the cigarette lighter.
Blocks under the hood
Under the hood, in the left part of the engine compartment, there may be 2 fuse blocks.
Fuse and relay block
To access the unit, you must remove the protective cover.
Marking
| 201 | 5A Alarm siren |
| 202 | 20A Auxiliary heater control unit |
| 5A Electric Drive (W242): Relay terminal 87 of the parking lock control unit | |
| 203 | 15A Front right block headlight |
| 5A Electric Drive (W242): Transmission control unit | |
| 204 | 25A Electronic stability control unit |
| 205 | 15A Left horn |
| The beep is right. | |
| 206 | 5A CDI control unit (engine 651) |
| Transmission control unit (Electric Drive (W242)) | |
| Brake booster vacuum pump relay (Electric Drive (W242)) | |
| Relay electric circuit terminal 87M (Electric Drive (W242)) | |
| 207 | 5A Relay electrical circuit terminal 87M (diesel) |
| High-voltage battery cooling shut-off valve (Electric Drive (W242)) | |
| Parking lock control unit (Electric Drive (W242)) | |
| 208 | 7.5A Relay terminal 87 (engines: 133, 607) |
| 5A Electric Drive (W242): Fan motor | |
| 209 | 15A Front left headlight |
| Electric Drive (W242): Reserve | |
| 210 | 5A Heated front window relay |
| Previous starter relay (from 03.11.2014) | |
| 211 | 7.5A CNG control unit (242.848) |
| 15A Heating circuit circulation pump (Electric Drive (W242)) | |
| 212 | 15A Cable lug electrical circuit terminal 87M3 (engines 133, 270) |
| Ventilation duct heating element (engine 651) | |
| Cooling system thermostat heating element (engine 651) | |
| EGR cooler bypass valve (engine 651) | |
| Lambda probe before the catalyst (engine 607) | |
| Boost pressure control servomechanism (engine 607) | |
| CDI control unit (engine 607) | |
| Electric Drive (W242): Electric drive coolant pump and charger | |
| 213 | 15A Terminal 87 cable end sleeve (engines 133, 270, 651) |
| Hall sensor camshaft (engine 607) | |
| CDI control unit (engine 607) | |
| Dosing valve (engine 607) | |
| Lambda probe after the catalyst (engine 607) | |
| Electric Drive (W242): Coolant pump 1 battery cooling | |
| 214 | 10A Terminal 87 cable end sleeve (motors 133, 270, 651) |
| 15A Electric Drive (W242): Coolant pump 2 battery cooling | |
| 215 | 20A Cylinder 1 ignition coil (petrol engines) |
| Cylinder 2 ignition coil (petrol engines) | |
| Cylinder 3 ignition coil (petrol engines) | |
| Cylinder 4 ignition coil (petrol engines) | |
| Dosing valve (engine 651) | |
| CDI control unit (engine 607) | |
| Boost pressure control servomechanism (engine 607) | |
| Dosing valve (engine 607) | |
| 5A Electric Drive (W242): | |
| Thermal control unit | |
| Transmission gateway control unit | |
| High-voltage electricity distributor (from 03.11.2014) | |
| 216 | 5A ME control unit (petrol engines) |
| Transmission control unit (engine 607) | |
| 217 | 25A Fully integrated dual clutch transmission control unit (724 transmission) |
| 218 | 5A Electronic stability control unit |
| 219 | 5A Electric Drive (W242): Parking lock control unit |
| 220 | 10A Transmission oil cooling system circulation pump (724 transmission) |
| 221 | 40A Electric Drive (W242): Vacuum pump |
| 222 | 7.5A Electric Drive (W242): Electric air conditioning compressor |
| 223 | Reserve |
| 224 | 7.5A DISTRONIC electrical control module |
| COLLISION PREVENTION ASSIST control module | |
| 225 | 6A Electric Drive (W242): Transmission control unit |
| 226 | 5A CNG control unit (242.848) |
| Charger control unit (Electric Drive (W242)) | |
| Power electronic equipment control unit (Electric Drive (W242)) | |
| 227 | 5A Electric Drive (W242): Power electronics control unit |
| 228 | 5A Electric Drive (W242): Electric car sound generator |
| 229 | 5A Front left headlight unit |
| 230 | 5A Electronic stability control unit |
| 231 | 5A Front right block headlight |
| 232 | 15A Headlight control unit |
| 233 | Reserve |
| 234 | 5A Transmission control unit (engine 607) |
| 10A Electric Drive (W242): High-voltage power distributor | |
| 235 | 7.5A Fan motor (motor 607) |
| Radiator louver actuator (engine 607) | |
| Air cooler circulation pump (engine 133) | |
| 236 | 40A SAM control unit |
| 237 | 40A Electronic stability control unit |
| 238 | 50A Heated windshield |
| 239 | 30A Wiper mode relay 1/2 |
| 240A | 25A Relay terminals 50 starters |
| 7.5A Electric Drive (W242): Transmission control unit | |
| 240B | 25A Relay terminal 15 (unsupported) |
| 241 | 7.5A Electric Drive (W242): High-voltage electric heater system |
| Relay | |
| J | Audible signal relay |
| K | Wiper speed relay 1/2 |
| L | Wiper relay on/off |
| M | Relay terminals 50 starters |
| Electric Drive (W242): Terminal 87C Relay | |
| N | Relay electrical circuit terminals 87M |
| THE | Transmission oil cooling system coolant circulation pump relay |
| Electric Drive (W242): Relay terminal 87 of the parking lock control unit | |
| P | Backup relay |
| Q | Relay terminal 15 (unprotected) |
| Electric Drive (W242): Brake booster vacuum pump power supply relay | |
| R | Relay terminals 15 |
| S | Relay terminals 87 |
| T | Heated windshield relay |
Fuse block
The high-power fuse block is located next to the fuse and relay block.
Scheme
Appointment
| F1 | 300A Generator / 400A Electric Drive (W242): DC-DC converter control unit |
| F2 | 200A Passenger compartment fuse box (Electric Drive (W242), and cars with petrol engine) |
| 250A Passenger compartment fuse box (diesel engines) | |
| F3 | 100A Electric power steering control unit |
| F4 | 40A SAM control unit |
| F5 | 80A Fan motor |
| F6 | 70A Fuel heating control unit (engine 607) |
| F7 | 125A DPF regeneration auxiliary heater control unit (engine 607) |
| F8 | 100A Glow Plug Output Module (Engines: 651, 607) |
| Relay | |
| F32k1 | Isolation relay (F32k1) |