Mercedes W168 – fuse and relay

The Mercedes W168 represents the first generation of the A-Class in the Mercedes-Benz lineup which was designated A140, A150, A160, A170, A180, A190, A200 and A210 and was produced in 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004. During this time, the model has been restyled. In this publication you will find information about the location of all electronic control units, a description of the fuses and relays Mercedes w168 with box diagrams and photo examples of their execution. Select the cigarette lighter fuse.

Mercedes 168

The purpose of the fuses and relays may differ from the one shown and depends on the year of manufacture and the level of equipment of your car.





1Air conditioning control unit – in the heater control panel
2Antenna signal booster
3Anti-theft system control unit – interior lamps
4Vehicle inclination sensor (anti-theft system) – in the anti-theft system control unit
5Horn of the anti-theft system
6Volume change sensors (anti-theft system) – in the anti-theft system control unit
7Anti-theft signal control unit – in the immobilizer control unit
9Auxiliary heater remote control receiver
10Battery – passenger side legroom
12Clutch control unit
13Diagnostic connector (DLC)
14Power window control unit – in the front power window control panel
15Left front power window control unit – in power window motor
16Left rear power window control unit – in power window motor
17Right front power window control unit – in power window motor
18Right rear power window control unit – in power window motor
19Fuse box/relay dashboard
20Fuse/Relay Box, Footwell
21Fuse/Relay Box, Engine Compartment
22Horns – behind the front bumper
23Electronic immobilizer control unit
24Immobilizer ring antenna – near the ignition switch
26Lighting control unit – in the headlight switch
27Multifunctional control unit – functions: central locking, direction indicators, sunroof – in the instrument cluster
28Navigation system control unit – in audio unit
29Ambient temperature sensor
30Parking system control unit
31Rain sensor – in the interior rearview mirror
32Seat heating control unit – in the switch block
33Side impact sensor, left
34Side impact sensor, right
35SRS electronic control unit
36Telephone network connection module
37Phone interface control unit
39Windshield Wiper Intermittent Relay – Windshield Wiper Motor

Passenger compartment

Fuse and relay box

The main fuse and relay box is located next to the battery, on the passenger side under a cover in the footwell. To remove the cover, turn the fastening clips.


Photo – example

Photo w168


Diagram mercedes w168


120A Gasoline engines:
Tank Vent Valve Fan Relay
Fuel injection control unit
Idle speed control unit
EGR valve
Lambda probe heater 1
Lambda probe heater 2
Diagnostic connector
boost relay
Boost valve (US models)
Fuel cut-off valve (US models)
10A Diesel engines:
Fan relay
Diesel power control unit
diaphragm valve
throttle valve
EGR valve
Catalyst temperature sensor
225A Engine control unit
Ignition coils
fuel injectors
Fuel pump relay
Electronic accelerator
Relay for blocking and disabling the starter
330A Vehicles without air conditioning: Engine cooling fan
40A Vehicles with air conditioning: Engine cooling fan
47.5A Engine control unit
540A Automatic clutch
630A Fuel pump relay
740A Vehicle lighting unit
830A Starter Interlock and Disable Relay
940A Wiper motor
1020/40A Hatch
Rear window cleaner
1115A Cigarette lighter
15A Steering column switch:
glass cleaner
Sound signal
washer pump
Radio navigation system
1230A Socket in trunk
Glove box light
CD changer
1330A Front door windows
7.5A Power windows for all doors
1410A Instrument panel (clock)
Wiper and washer relay
Mobile phone
1510A Airbag unit
Child seat recognition unit
Side airbag sensor
1615A Exterior mirror drive and mirror heater
Parking assistance
1715A Horn
1810A Instrument panel
Transponder and signal receiver from the remote control
ECM relay
Fan relay
1930A Drawbar
2015A Drawbar
2115A Drawbar
2225A Audio system
237.5A Mirror illumination
24Not used
25Not used
26Not used
27Not used
2810A Instrument panel
Power windows
2915A Central locking
Seat position recognition unit
307.5A Transponder and remote control signal receiver
Electronic instrument panel
3125A Rear window heater
3215A Mobile phone
Radio receiver or radio navigation system
CD changer
Interior lighting
3330A Power windows
3430A Fuel filter heater
40A Supercharging. (US models)
3510A Burglar alarm control unit
2x light and sound alarm relays
3625A Heated front seats
3710A Program switch
Coolant heater relay
3810A Air conditioning compressor
Air mixing damper motor
Cabin air temperature sensor
Washer jet heater
397.5A Lighting module
reversing lamp
4010A Brake lights
4110A Air conditioning compressor
Diagnostic connector
42Power windows
4315A ESP
Brake light switch
4410A Transmission or automatic clutch control unit
4530A Interior heater blower
air conditioner fan
4680A Fuse for on-board network
4760A Power steering pump
4860A Diesel engines: Preheat control unit
К7Fuel pump relay (002 542 13 19)
К8Fuel and ignition control unit relay (002 542 25 19)
К9ESP/VGS relay or ESP/automatic transmission. VGS gearbox control unit (002 542 25 19)
К10Rear window heater relay (002 542 13 19)

Fuses number 11 and 12 are responsible for the cigarette lighters.

Fuse box

Another fuse box is located on the back of the instrument panel, also closed with a protective cover.


Photo 1


  1. 7,5A – Left low beam headlight
  2. 7,5A – Right low beam headlight
  3. 15A – High beam, high beam indicator
  4. 7,5A – Left parking light, Rear left marker
  5. 15A – Right parking light, Right tail light, License plate light, Instrument panel, terminal 58
  6. 15A – Fog lights, Left rear fog light

Engine compartment

Under the hood, on the right side of the engine compartment, a block with a relay is installed.

Location 2


Diagram 2


К1washer pump relay
К2.0horn relay
К2.1stability control relay (ESP)
К3relay for blocking and disabling the starter
К4radiator fan relay
К5stability control pump (ESP) relay
К6air pump relay (USA Models)


Found a mistake or have something to add – write in the comments.

Comments 2

  • I’ve got a problem with the indicators on my w168 if I use the left indicator, my right indicator flickers

  • My engine check light its not showing when i turn on my Mercedes Benz A160 2002 MODEL

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