Mercedes-Benz C-Class W205 Fuses: Complete Guide 2014-2021

BySerge Barrett

The Mercedes-Benz C-Class W205, produced from 2014 to 2021, features a sophisticated electrical architecture with multiple fuse boxes distributed throughout the vehicle. Understanding the fuse layout is essential for diagnosing electrical faults, replacing blown fuses, and avoiding costly dealer visits for simple repairs. This guide covers every fuse box location, each fuse’s amperage and function, and practical tips for safe fuse maintenance on the W205 platform.

Fuse Box Locations on the Mercedes-Benz C-Class W205

The W205 C-Class has three primary fuse box locations. Knowing where each one is located saves time during fault-finding.

  • Engine Compartment Fuse Box – located on the left side of the engine bay, near the battery and brake fluid reservoir
  • Interior Fuse Box (Front SAM – Signal Acquisition Module) – located behind the glove box on the passenger side, or under the dashboard depending on trim
  • Rear SAM Fuse Box – located in the trunk, under the floor panel on the left side near the spare wheel well

Engine Compartment Fuse Box – W205 C-Class

The engine bay fuse box handles high-current circuits and critical powertrain components. Always disconnect the ignition before accessing this box.

  • F1 – 80A – Alternator / Main Power Supply
  • F2 – 50A – Front SAM Control Unit Feed
  • F3 – 40A – ABS / ESP Hydraulic Unit Motor
  • F4 – 40A – Electric Power Steering (EPS)
  • F5 – 30A – Engine Control Unit (ECU) Main Supply
  • F6 – 30A – Transmission Control Module (TCM)
  • F7 – 30A – Cooling Fan Low Speed
  • F8 – 30A – Cooling Fan High Speed
  • F9 – 25A – Fuel Pump Relay Supply
  • F10 – 25A – AIRMATIC Suspension Compressor (if equipped)
  • F11 – 20A – Starter Motor Relay
  • F12 – 20A – Ignition Coil Pack Supply
  • F13 – 20A – Injector Supply Rail
  • F14 – 15A – Lambda / Oxygen Sensor Heaters
  • F15 – 15A – Turbocharger Wastegate Actuator
  • F16 – 10A – Camshaft Adjustment Solenoids
  • F17 – 10A – Engine Coolant Thermostat
  • F18 – 10A – Brake Booster Vacuum Pump (Diesel)
  • F19 – 10A – AdBlue / SCR Dosing Unit (Diesel BlueTEC)
  • F20 – 10A – EGR Valve Control

Front SAM (Interior) Fuse Box – W205 C-Class

The Front SAM module manages interior electronics, lighting, comfort systems, and driver assistance features. This is the most commonly accessed fuse box for everyday electrical issues.

  • F21 – 25A – Heated Rear Window
  • F22 – 25A – Front Wiper Motor
  • F23 – 20A – Heated Front Seats – Driver
  • F24 – 20A – Heated Front Seats – Passenger
  • F25 – 20A – Power Window – Front Left (Driver)
  • F26 – 20A – Power Window – Front Right (Passenger)
  • F27 – 20A – Power Window – Rear Left
  • F28 – 20A – Power Window – Rear Right
  • F29 – 15A – Interior Lighting / Ambient Lighting
  • F30 – 15A – Instrument Cluster / Combi Instrument
  • F31 – 15A – Infotainment System / COMAND Head Unit
  • F32 – 15A – Telephone / Bluetooth Module
  • F33 – 15A – Navigation / Antenna Module
  • F34 – 15A – Rain / Light Sensor
  • F35 – 10A – Electric Mirror Adjustment and Folding
  • F36 – 10A – Central Locking / Door Lock Actuators
  • F37 – 10A – Diagnostic Interface / OBD Port (Pin 16)
  • F38 – 10A – Airbag Control Unit (SRS)
  • F39 – 10A – Active Parking Assist / Ultrasonic Sensors
  • F40 – 10A – Lane Keeping Assist / Attention Assist
  • F41 – 10A – Steering Column Switches and Controls
  • F42 – 10A – Turn Signal / Hazard Light Relay
  • F43 – 10A – Horn
  • F44 – 10A – Cigarette Lighter / 12V Accessory Socket Front
  • F45 – 10A – Glove Box Illumination and Lock
  • F46 – 7.5A – ACC (Adaptive Cruise Control) Module
  • F47 – 7.5A – Front Camera / Collision Prevention Assist
  • F48 – 5A – Interior Rearview Mirror (Auto-Dimming)
  • F49 – 5A – Sunroof / Panoramic Roof Control
  • F50 – 5A – Memory Seat Module

Rear SAM Fuse Box – W205 C-Class

The Rear SAM is located in the trunk and manages rear-end electrical systems including the fuel system, tail lights, and rear comfort functions.

  • F51 – 25A – Rear Window Wiper (Estate / T-Model)
  • F52 – 20A – Fuel Pump Primary Circuit
  • F53 – 20A – Rear Seat Heating
  • F54 – 15A – Tail Light Cluster – Left
  • F55 – 15A – Tail Light Cluster – Right
  • F56 – 15A – Reversing Camera / Parking Assist Rear
  • F57 – 15A – Trailer Hitch / Towing Module (if equipped)
  • F58 – 10A – Boot / Trunk Lighting and Release
  • F59 – 10A – Number Plate / License Plate Light
  • F60 – 10A – Rear 12V Accessory Socket
  • F61 – 10A – Rear Differential Lock (4MATIC / AMG variants)
  • F62 – 7.5A – Rear SAM Control Unit Keep-Alive Memory

Fuse Types Used in the W205 C-Class

  • Mini blade fuses (ATO/ATC) – used in interior and rear SAM boxes for low-current circuits (5A–25A)
  • Maxi blade fuses – used in the engine bay box for high-current circuits (30A–80A)
  • Micro2 fuses – used in some late-production W205 models (2019–2021) for space-saving applications

How to Check and Replace a Fuse on the W205

  • Always switch off the ignition and remove the key before inspecting fuses
  • Use the plastic fuse puller tool stored inside each fuse box lid
  • Visually inspect the fuse element through the transparent body – a broken wire indicates a blown fuse
  • Use a multimeter set to continuity mode for definitive testing without removing the fuse
  • Replace only with a fuse of identical amperage – never uprate a fuse
  • If a fuse blows repeatedly, a short circuit or overloaded component exists – diagnose before replacing again
  • Mercedes-Benz W205 fuse box diagrams are printed on the inside of each box cover and in the owner’s manual Section 7.2

Common Electrical Faults and Associated Fuses on the W205

  • COMAND screen not working – check F31 (15A, Infotainment)
  • OBD scanner won’t connect – check F37 (10A, Diagnostic Port)
  • Power windows inoperative – check F25–F28 (20A, individual window circuits)
  • Central locking failure – check F36 (10A, Door Lock Actuators)
  • Rear camera not displaying – check F56 (15A, Reversing Camera)
  • Cigarette lighter dead – check F44 (10A, Accessory Socket)
  • Heated seats not working – check F23 or F24 (20A, Seat Heating)

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