Smart Fortwo / Forfour (2014-2017) Fuse Diagram

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Fuse box diagram (fuse layout), location, and assignment of fuses and relays Smart Fortwo / Forfour (A453, C453, W453) (2014, 2015, 2016, 2017).

Smart Fortwo / Forfour (2014-2017)

Checking and Replacing Fuses

The fuses in your vehicle serve to close down faulty circuits. If a fuse blows, all the components on the circuit and their functions stop operating. A blown fuse can be identified by the melted metal strip inside it. Blown fuses must be replaced with fuses of the same rating, which you can recognize by the color and value.

Before replacing fuses:

  • Set the parking brake.
  • Make sure the gear selector lever is in park position P.
  • Turn off all electrical accessories.
  • Turn off the engine.
  • Remove the key from the starter switch.

A blown fuse must be replaced by an appropriate spare fuse (recognizable by its color or the fuse rating given on the fuse) of the amperage recommended in the fuse chart.

  • From the fuse chart determine which fuse belongs to the malfunctioning accessory or component.
  • Remove the respective fuse.
  • Replace the defective fuse with a new one of the same amperage.

If a newly inserted fuse also blows, have the cause traced and rectified at a qualified specialist workshop, e.g. an authorized Mercedes-Benz Center.

Notice

  • Only use fuses approved by Smart with the specified amperage for the system in question and do not attempt to repair or bridge a blown fuse this may cause an overload leading to a fire, and/or cause damage to electrical components and/or systems. Contact a smart center if you encounter any electrical problems.
  • Never use a fuse with a higher amperage rating, or any other object, in place of a fuse. This may cause extensive damage and possibly a fire.
  • We recommend always carrying replacement fuses in the vehicle.

Fuse box in the glove compartment

Fuse box in the glove compartment (location)

  • Open the front-passenger door.
  • Open the glove box.
  • To open: open cover.
  • Replace the defective fuse.
  • To close: insert and fold in cover until it engages.
  • Close the glove box.

Fuse box in the glove compartment (diagram)

Fused functionA
1Rear roof rack electrical connection20
2--
3--
4--
5Driver-side SAM control unit25
6Driver-side SAM control unit25
7Driver-side SAM control unit25
8Center SAM control unit15
Radio
Radio over connector sleeve for terminal 15 R
9--
10Horn15
11Battery sensor and driver-side SAM control unit5
12Front cigarette lighter with ashtray illumination15
13--
14Automatic transmission protected through connector sleeve for circuit 3020
Diagnostic connector
Valid for electric vehicle:
   Fused circuit 30 connector sleeve
   Diagnostic connector
15Supply for fused circuit 30 connector sleeve15
16Motor electronics protected through connector sleeve for circuit 305
Valid for electric vehicle: Supply for fused circuit 30 connector sleeve
17Supply protected through connector sleeve for circuit 3015
18Brake lights switch10
19Outside mirror adjustment switch5
20Transponder coil3
Electronic Stability Program control unit and brake light switch
Protected through connector sleeve for circuit 30
21Light functions protected through connector sleeve for circuit 3010
22Steering wheel angle sensor5
Dual-clutch transmission control unit
23--
24Center SAM control unit15
25Center SAM control unit10
26Center SAM control unit15
27Center SAM control unit20
28Driver-side SAM control unit10
29Driver-side SAM control unit10
30Combination switch15
Alarm siren
Supply for fused circuit 30 connector sleeve (valid for electric vehicle)
31Instrument cluster and additional instruments10
32--
33Supplemental Restraint System control unit5
34Combination switch5
35Electrical power steering control unit5
36Center SAM control unit5
37Driver-side SAM control unit30
38Air conditioning power supply solenoid switch40
39Starter30
Through starter relay
39Valid for electric vehicle: Blower motor40
1/1Valid for electric vehicle: Electric vehicle circuit 30 connector sleeve supply10
1/2Valid for electric vehicle:  -
   Brake booster vacuum pump control unit
   Power electronics control unit
1/3--
1/4Sound system amplifier control unit20
1/5Dual clutch transmission control unit5
Valid for electric vehicle: Electric drive control unit
1/6Left front power window motor and right front power window motor25
1/7Left electrically adjustable and heated outside mirror and right electrically adjustable and heated outside mirror5
1/8Valid for electric vehicle:25
   Front passenger seat heater control unit
   Driver seat heater control unit
1/9--
1/10Valid for electric vehicle: Steering wheel heater relay-
2/1Supply for soft top control drive unit20
2/2Supply for soft top control drive unit20
2/3--
2/4--
Relay
K1Heated rear window/outside mirrors relay
K2Front power window relay
K3Sliding roof relay
K4Front headlamps relay
K5Starter relay
K6Fanfare horn relay
K7Valid for electric vehicle: Steering wheel heater relay

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Fuse box in the front area

Fuse box in the front area (location)

Fuse box in the front area (diagram)

Fused functionA
1Heated rear window over relay for heated rear window/outside mirrors30
2Front passenger seat heater control unit30
Driver seat heater control unit
Valid for electric vehicle: Brake booster vacuum pump control unit
3Supply for Electronic Stability Program control unit25
4Valid for electric vehicle: -40
Electrical fuse 1 and electrical fuse 2
Sliding roof relay25
5Supply for internal combustion engine fuse and relay module60
6Dual clutch transmission control unit50
Protected through connector sleeve for circuit 30
Valid for electric vehicle: Vehicle interior fuse and relay module supply40
7Fan motor30
Over fan relay
Fan solenoid switch30
ICE combustion engine cooling
8--
9Valid for USA:Secondary air injection pump60
Valid for electric vehicle:
   Heater for high-voltage battery
   Over heater relay for high-voltage battery
Relay
K1Fan relay
Battery clamp fuses

Battery clamp fuses

Fused functionA
F1Electrical fuse 3A (F108f3A) and electrical fuse 3B (F108f3B)200
Valid for electric vehicle:
   Power supply fuse and relay module (F1)
   DC/DC converter control unit
F2AVehicle interior fuse and relay module supply (F2)70
Protected through connector sleeve for circuit 30
Connector sleeve for circuit 30
F2BElectrical power steering control unit60
F3AVehicle interior fuse and relay module supply (F2)70
Ignition lock
Protected through connector sleeve for circuit 30
Connector sleeve for circuit 30
F3BElectronic Stability Program control unit50

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Power supply fuse and relay module

Power supply fuse and relay module (location)

Power supply fuse and relay module (diagram)

Fused functionA
1Internal combustion engine relay moduleDiode
Valid for electric vehicle: -
2Valid for USA: Supply for vacuum pump relayDiode
Valid for electric vehicle:15
   Transmission mode recognition sensor
   Electric drive control unit
3Fuel pump with fill level sensor and temperature sensor20
Valid for electric vehicle: Electric vehicle drive motor fan relay40
4Supply for fused circuit 30 connector sleeve25
Valid for electric vehicle: Battery cooling system coolant pumps relay30
5Supply for connector sleeves for circuit 8715
Valid for electric vehicle: Battery cooling system coolant pump15
6Refrigerant compressor relay15
Valid for electric vehicle:5
   Battery management system control unit
   Electric drive control unit
7Fan10
Through fan relay
Valid for electric vehicle: Power electronics control unit power supply connector sleeve supply20
8Dual clutch transmission control unit10
Valid for electric vehicle: Circuit 87 supply connector sleeve15
Relay
K1Engine function circuit 87 relay
K2Fan relay
K3Ignition coils/fuel pump actuation relay
K4Valid for electric vehicle: Battery cooling system coolant pumps relay

 

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