Mercedes ML W166 (GL X166) fuse and relay

Mercedes ML W166 represents the third generation of the Mercedes-Benz M-Class SUV which was produced in 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020 and delivered worldwide. During this time, the model has been restyled. This information will also be useful to the owners of the Mercedes GL X166 and Mercedes GLS X166, because these cars have similar electrical circuits. In it you can find a description of the fuses and relays Mercedes 166 with box diagrams, photo examples of their performance and locations. Note the fuse responsible for the cigarette lighter.

Mercedes 166

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

Engine compartment

Location

Layout

location

Assignment

  • F32/3 – Power fuse box
  • F58 – Fuse and relay box

Fuse and relay box

Photo – example

Photo of fuse box 166

Diagram

Diagram fuse box Mercedes 166

Designation

201Reserve
20220A Auxiliary heater heater
2035A Alarm Siren
20425A Electronic motion stabilization control unit
20515A Left horn
Right horn
206Reserve
207Reserve
208Reserve
209Reserve
210Reserve
211Reserve
212Reserve
2137.5A Valid for engines 642, 651:
CDI control unit
Valid for engine 157, 276, 278:
ME control unit
21415A Valid for engine 157, 276, 278:
ME control unit
Valid for vehicles with engine 651:
CDI control unit
BlueTEC:
Nox sensor control unit
21515A Valid for vehicles with engine 157, 276, 278:
Electrical plug connection engine/engine compartment (pin 7)
Valid for vehicles with engine 642:
Electrical plug-in connection for motor/engine compartment (pin 7) via terminal 87 D3 cable gland
Radiator shutter actuator
Valid for vehicles with engine 651:
Electrical plug connection engine/engine compartment (pin 7)
Radiator shutter actuator
21615A Valid for engine 157, 276, 278:
Cable termination, terminal 87D2
Valid for vehicles with engine 642:
CDI control unit
Electrical plug connection engine/engine compartment (pin 6)
Adjustable left engine mount
Adjustable right engine mount
Valid for vehicles with engine 651:
Fan motor
CDI control unit
Electrical plug connection engine/engine compartment (pin 6)
Adjustable engine mount, left (Y123) Adjustable engine mount, right
21720A Valid for engine 157, 276, 278:
Electrical plug connection engine/engine compartment (pin 5)
Valid for engines 642, 651:
CDI control unit
Electrical plug connection engine/engine compartment (pin 5)
218Reserve
21910A Valid for engine 278, 157: Charge air cooler circulation pump
220Reserve
222Reserve
223Reserve
224Reserve
225Reserve
226Reserve
227Reserve
228Reserve
2297.5A Front left headlight
2305A Control unit for electronic stability control
2317.5A Front right headlight
23215A Fully integrated gearbox control unit
Vehicles without “ECO Start-Stop” function: Additional transmission oil pump control unit
23315A Headlight control unit
2345A Electrical control module DISTRONIC
23520A Heated wiper blades
236Reserve
23715A KP 722.9: Servo drive module for automatic transmission for DIRECT SELECT system
23840A Compressor AIRMATIC
23930A Wiper motor
240а30A Vehicles without “ECO Start-Stop” function: Starter
240b30A Vehicles with “ECO Start-Stop” function: Engine compartment power fuse box
241Reserve
Relay
JHorn relay
KWiper Mode Relay 1/2
LWiper relay on/off
MStarter terminal 50 relay
NRelay el. circuit terminals 87M
OTurbocharger relay
PReserve relay
QTerminal 15 relay (no support)
RRelay terminal 15
SRelay for heated wiper blades
TAIRMATIC relay

Power fuse box

Photo

Photo 1

Diagram

Diagram 1

Allocation

25040A SAM control unit
25140A SAM control unit
25240A SAM control unit
25330A Front left door control unit
25430A Rear left door control unit
255200A Battery compartment power fuse box
256150A Rear fuse box
257150A Diesel engine: Additional electric heater

It is possible to install some elements of the relay outside these blocks, for example, a relay for heating hoses to washer nozzles.

Relay

Passenger compartment

Location

Layout

location 2

Appointment

  • F3 / 2, F3 / 3 – Fuse box in the instrument panel
  • F4 – Main fuse and relay box in the rear
  • F32/4 – Power fuse box
  • F33 – Battery compartment fuse box
  • F270 – Buffer battery fuse

Fuse and relay box

The main box with fuses and relays in the passenger compartment is located under the rear seat and is closed with a protective cover.

Photo 2

Diagram

Diagram 2

Decoding

1005A Audio module
COMAND control module
Electrical plug connection for external navigation
10120A Trailer detection control unit
1027.5A Driver’s seat control unit
1037.5A Front passenger seat control unit
1045A Antenna Amplifier / Mobile Phone Compensator
Bluetooth® module
1055A Holder for navigation module
1065A Tailgate control unit
10710A Release module, 2nd row of seats, left
Release module, 2nd row of seats, right
108Reserve
109Reserve
1105A AdBlue® control unit
11115A Trailer socket
1125A Fuel pump control unit
1135A Electric parking brake control unit
1145A Switch for exterior lighting
1155A Trailer detection control unit
1165A Termination of terminal 87 of the radar control unit
COLLISION PREVENTION ASSIST control module
1175A Night vision control unit
118Reserve
1195A Transfer case control unit
1205A Fuel quality sensor
Digital tachograph control unit
121Reserve
122Reserve
123Reserve
12430A Electrical plug connection for the Elektric Brake Control function
125Reserve
12615A Trailer recognition control unit
12730A Driver seat control unit
12820A Trailer recognition control unit
12930A Front passenger seat control unit
13020A Trailer recognition control unit
131Reserve
13225A Fuel pump control unit
1335A Radio remote control receiver for auxiliary heater
1345A Seat occupied recognition pressure sensor
Occupancy recognition and AKSE, front passenger seat
1355A Glove box light
1367.5A Control unit for passenger restraint system (Supplemental Restraint System)
1375A Electric fuse preparation for installation of the Electronic Toll Collection system
Electronic equipment rear view camera
Electrical plug connection for external navigation
13815A Active roll stabilization control unit
139Reserve
1407.5A AdBlue® control unit
14115A AdBlue® control unit
14220A AdBlue® control unit
143Reserve
144Reserve
1457.5A Cup holder
14630A Rear window notch filter
14730A Audio module
COMAND control module
14815A Cigarette lighter heating element
Detachable cup holder connection
1495A Socket 115 V
15020A Socket in trunk
15120A Socket, 2nd seat row, left
Socket in the 2nd row of seats on the right
15230A Rear compartment systems control unit
15325A AC/DC converter control unit
15440A Tailgate control unit
155Reserve
156Reserve
15715A Tailgate wiper motor
Relay
АRelay socket terminals 15R2
BHeated rear window relay
CBackup relay
DAdBlue® relay
ERelay terminal 15
FRear window wiper relay
GRelay terminal 15R1
HBackup relay
IBackup relay

Fuses 148 – 151 are responsible for the cigarette lighter.

Fuse box in the panel

A fuse box is installed at the right end of the instrument panel, behind a protective cover.

access to fuse box

Diagram

Diagram 3

Assignment

  • 10 7.5A Electronic ignition lock control unit
  • 11 10A Steering column electronic module control unit
  • 12 5A Instrument cluster
  • 13 15A Auxiliary fan electronic control
  • 14 5A Diagnostic connector
  • 15 5A Upper control box
  • 16 Reserve
  • 17 Reserve
  • 18 Reserve
  • 19 15A Climate Control Panel
  • 20 5A Steering column electronic module control unit
  • 21 7.5A Audio/ COMAND display
  • 22 Reserve

Battery compartment fuse box

In a niche next to the battery, another fuse box is installed.

Photo 4

Diagram

Diagram 4

Designation

3040A Speaker amplifier control unit
30A Woofer Amplifier
3140A Engine compartment fuse and relay module
3240A Fan regulator
3340A Front left reversible seat belt pretensioner
3440A Rear fuse box
3540A Front right seat belt reversible pretensioner
3640A Fuse box, terminal 30, front panel
3740A Test lead
38Reserve
39Reserve
4025A Electronic rear air conditioning fan control
41Reserve
42Reserve
43Reserve
44Reserve
455A Digital tachograph control unit
46Reserve
4710A Speaker amplifier control unit
4830A Rear compartment systems control unit
495A EDW/Tow protection/Interior monitor control unit
505A Emergency call system control unit
515A Antenna amplifier FM 1, AM, ZV and KEYLESS-GO
5230A Front right door control unit
5315A Ceiling control box
54Test lead
5530A Rear compartment systems control unit
5615A KeyLess-Go control unit
5730A Rear right door control unit
5830A Transfer box control unit
597.5A Control unit for passenger restraint system (Supplemental Restraint System)
607.5A Ceiling control box
61Reserve
6215A AIRMATIC control unit
6320A Panoramic sliding sunroof control module
Sliding sunroof control module
6430A Air pump for multi-contour seat
6530A Fuse box, terminal 30g, front panel
66Reserve
6730A Electric parking brake control unit
6830A Electric parking brake control unit
MF15A Pin 1: Audio module / COMAND system control panel
Contact 2:
Bottom Control Panel
Off-road driving mode control panel
Pin 3: Parking assistance control unit
Pin 4: Control unit for electronic stability control
Pin 5: SAM control unit
Pin 6: Speaker amplifier control unit
MF25A Pin 1: HBF control unit
Pin 2: Tire pressure monitoring control unit
Contact 3:
Digital audio broadcasting control unit
Satellite Digital Audio Radio (SDAR) control unit
Pin 4: Multi-function camera
Pin 5: Multimedia interface control unit
Pin 6:
Rear View Camera
360° camera control box
MF35A Pin 1: Rear left display
Pin 2: Rear right display
Contact 3:
TV tuner (analog/digital)
Digital TV tuner
Pin 4: DVD player
Pin 5: Control unit for video and radar sensors
Contact 6: Reserve
MF4Contact 1: Reserve
Contact 2: Reserve
Contact 3: Reserve
Contact 4: Reserve
Contact 5: Reserve
Contact 6: Reserve

Power fuse box

This high power fuse box is also located near the battery.

Photo 5

Diagram

Diagram 5

Allocation

  1. 40A Control unit for electronic stability control
  2. Reserve
  3. 30A Vehicles with ECO Start-Stop function: Engine compartment fuse and relay module
  4. Reserve
  5. 150A Engine compartment fuse and relay module
  6. 125A Fan motor
  7. 300/400A Power fuse box in passenger compartment
  8. 100A Electric power steering control unit

 

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