The first generation of the A-Class was introduced in the autumn of 1997. The Mercedes-Benz W168 was a unique model in the manufacturer's lineup: alongside its exceptionally compact body, it featured front-wheel drive. Another key feature was its “sandwich” floor safety concept for frontal impact absorption. This article provides detailed fuse box diagrams for the Mercedes-Benz A-Class W168 (1st Gen; A140, A150, A160, A170, A180, A190, A200, and A210) produced from 1997 through 2004.
Below you will find the locations and photos of the power distribution/fuse boxes. Fuses for the **Cigarette Lighter** and **Fuel Pump** are highlighted in bold.
Passenger Compartment
Two power distribution boxes located in the passenger compartment protect the vehicle’s electrical circuits.
Main Fuse Box
Located in the front passenger footwell beneath the floor access panel.
Overview of the Mercedes-Benz A-Class W168 main fuse panel.
| Diagram | ||
|---|---|---|
|
||
| No. | Circuit / Protected Component | Rating (A) |
| 1 | Evaporative emission (EVAP) purge valve | 20 10 (Diesel) |
| Cooling fan relay | ||
| Engine control module (ECU) | ||
| Idle speed control module | ||
| EGR valve | ||
| Heated oxygen sensor 1 (Lambda probe) | ||
| Heated oxygen sensor 2 (Lambda probe) | ||
| Diagnostic link connector (DLC) | ||
| [Cruise control / Tempomat] | ||
| Secondary air injection relay and solenoid valve (US models) | ||
| Fuel shut-off valve | ||
| Cooling fan relay / Diesel power control module | 10 (Diesel) | |
| Diaphragm valve | ||
| Throttle body actuator | ||
| EGR valve | ||
| Catalytic converter temperature sensor | ||
| 2 | Ignition coils / Engine control unit (ECU) | 25 (Diesel) |
| Fuel injectors | ||
| Fuel pump fuse | ||
| Electronic throttle control (Drive-by-wire) | ||
| Starter lockout and shutdown relay | ||
| 3 | Radiator blower fan [with Air Conditioning] | 30, 40 |
| 4 | Engine control module (ECM/ECU) | 7.5 |
| 5 | Automated manual transmission / Automatic clutch (AKS) | 40 |
| 6 | Fuel pump relay | 30 |
| 7 | Exterior lighting control module | 40 |
| 8 | Starter lockout and shutdown relay | 30 |
| 9 | Windshield wiper motor | 40 |
| 10 | Power sunroof | 40 |
| Rear window wiper motor | 20 | |
| 11 | Steering column combination switch: | 15 |
| - Windshield wipers | ||
| - Horn | ||
| - Windshield washer pump | ||
| - Radio / Navigation system controls | ||
| - Cigarette lighter fuse (Mercedes W168) | ||
| 12 | Luggage compartment power socket, radio, glove box light, CD changer | 30 |
| 13 | Front power windows | 30 |
| Power windows (all doors) | 7.5 | |
| 14 | Instrument cluster (clock), wiper/washer relay, [Mobile phone] | 10 |
| 15 | Airbag control module (SRS) | 10 |
| Automatic child seat recognition module | ||
| [Side airbag sensor] | ||
| 16 | Power heated exterior mirrors, [Parktronic / Parking assist] | 15 |
| 17 | Horn | 15 |
| 18 | Instrument cluster | 10 |
| Immobilizer transponder and remote control receiver | ||
| Engine control unit (ECU) main relay | ||
| 19 | Trailer hitch / Towbar socket | 30 |
| 20 | 15 | |
| 21 | 15 | |
| 22 | Audio system / Radio | 25 |
| 23 | Not used | |
| 24 | Not used | |
| 25 | Not used | |
| 26 | Not used | |
| 27 | Not used | |
| 28 | Instrument cluster | 10 |
| [Power windows] | ||
| 29 | Central locking system | 15 |
| Seat occupancy / position sensor module | ||
| 30 | Immobilizer transponder and remote control receiver | 7.5 |
| Electronic instrument cluster | ||
| 31 | Heated rear window (Rear defroster) | 25 |
| 32 | [Mobile phone] | 15 |
| [Radio / Navigation system] | ||
| [CD changer] | ||
| Interior lighting | ||
| 33 | Power windows | 30 |
| 34 | Fuel filter heater or secondary air pump (US models) | 30 / 40 |
| 35 | [Anti-theft alarm control module] | 10 |
| Hazard light and audible alarm relays | ||
| 36 | Heated front seats | 25 |
| 37 | [Transmission program selector switch] | 10 |
| Auxiliary coolant heater relay | ||
| 38 | Air conditioning compressor | 10 |
| Air blend flap actuator motor | ||
| Interior temperature sensor | ||
| Heated windshield washer nozzles / fluid heater | ||
| 39 | Exterior lighting module | 7.5 |
| Tail lights | ||
| 40 | Brake lights (Stop lamps) | 10 |
| 41 | Air conditioning compressor, Diagnostic link connector (DLC) | 10 |
| 42 | Power windows | 30 |
| 43 | ESP brake light switch | 15 |
| 44 | Transmission control unit (TCU) or automatic clutch (AKS) | 10 |
| 45 | Blower motor (Heater / A/C fan) | 30 |
| 46 | Onboard electrical system / Main power supply | 80 |
| 47 | Electro-hydraulic power steering pump | 60 |
| 48 | Glow plug control module | 60 |
| (Diesel models) | ||
| No. | Relay Assignment | |
| K7 | Fuel pump relay (Mercedes W168) | |
| K8 | Engine control module / Ignition circuit relay (ESP / VGS or ESP / Automatic transmission) | |
| K9 | VGS = Electronic transmission control unit | |
| K10 | Heated rear window relay | |
Auxiliary Fuse Box
Located on the side of the dashboard, adjacent to the rotary light switch panel.
| Diagram | ||
|---|---|---|
|
||
| No. | Circuit / Protected Component | Rating (A) |
| 1 | Left headlight (Low beam) | 7.5 |
| 2 | Right headlight (Low beam) | 7.5 |
| 3 | High beam headlights, high beam indicator light | 15 |
| 4 | Left front and rear parking / side marker lights | 7.5 |
| 5 | Right front and rear parking / side marker lights, license plate lights, instrument cluster illumination | 15 |
| 6 | Front fog lights | 15 |
Engine Compartment
The relay module box is located on the right side of the engine compartment under a protective plastic cover. To access the relays, remove the three retaining screws, release the plastic clips, and lift off the cover.
Relay box access detail.
| Diagram | |
|---|---|
|
|
| No. | Description |
| 1 | Windshield washer pump |
| 2 | Horn |
| 3 | Brake light suppressor / lockout relay |
| 4 | Starter lockout / interlock relay |
| 5 | Radiator cooling fan relay |
| 6 | ABS / ESP hydraulic pump |
| 7 | Secondary air injection pump (Petrol models) |
Overview of Electrical Component Locations
General layout of electrical components in the Mercedes-Benz W168:
1. Air conditioning control module (integrated into heater control panel);
2. Antenna amplifier;
3. Anti-theft alarm control module (interior lighting);
4. Tow-away / tilt sensor (integrated into anti-theft control module);
5. Anti-theft alarm siren/horn;
6. Interior motion / volumetric sensors (integrated into anti-theft control module);
7. Anti-theft alarm signal control module (integrated into immobilizer);
9. Auxiliary heater remote control receiver;
10. Battery (front passenger footwell);
12. Automatic clutch actuator control module (AKS);
13. Data Link Connector (DLC / OBD-II);
14. Power window master control module (center console panel);
15. Front left power window module (integrated into window motor);
16. Rear left power window module (integrated into window motor);
17. Front right power window module (integrated into window motor);
18. Rear right power window module (integrated into window motor);
19. Auxiliary fuse box (dashboard);
20. Main fuse and relay panel (passenger footwell);
21. Engine compartment relay box;
22. Horn (behind front bumper);
23. Immobilizer control module;
24. Immobilizer transponder coil / ring antenna (ignition switch);
26. Exterior light switch module;
27. Multifunction control module (Central locking, turn indicators, sunroof — integrated into instrument cluster);
28. Navigation system control unit (integrated into audio head unit);
29. Ambient / cabin temperature sensor;
30. Parktronic control module (PTS);
31. Rain sensor (behind interior rearview mirror);
32. Heated seat control module (switch panel);
33. Left side-impact airbag sensor;
34. Right side-impact airbag sensor;
35. Airbag control module (SRS);
36. Cellular network interface module;
37. Hands-free telephone control module;
39. Intermittent wiper relay (windshield wiper motor assembly).