Fuses

This page describes fuse boxes, fuses and relays as of W220 facelift vehicles (from 30/09/2002).

The major difference in pre-facelift vehicles is that instead of four fuse boxes (two in the engine compartment, one under the back seat, and one in the side of the dashboard), pre-facelift vehicles have three, omitting the fuse box in the side of the dashboard.

Fuse charts for all vehicles in compact printable and searchable form are available for download in the section 'Fuse Charts' below.

It is recommended that you keep a printed version of the charts in a plastic sleeve with the spare fuses in the spare wheel well.

Fuse Ratings and Colour Codes

Ampere	Colour
5	Beige
7.5	Brown
10	Red
15	Blue
20	Yellow
25	White
30	Green
40	Amber
50	Red
60	Blue

Left fuse box (F1)

Located in engine compartment left.

Fuses

No.	Rating	Function	Comment
f1	40A	Wiper recess heating
f2	50A	ESP
f3	15A	Adjustable steering column
f4	15A	Adjustable steering column
f5	40A	Windscreen wipers
f6
f7
f8
f9	20A	ABC suspension; Air suspension	Permanently powers Airmatic control module.
f10	15A	Windshield washer system
f11	5A	Electronic toll collection
f12
f13	40A	Adjustable mirror, left; Automatic dimming exterior mirror; Driver seat adjustment; Driver seat heating; Entrance lights; Exterior mirror indicators, left/right; Folding exterior mirror; Heated mirror; Interior mirror adjuster; Power locking; Power window, driver seat; Power window, passenger seat; Power window, rear left; Power window, rear right; Remote closing and locking trunk lid; Remote trunk lid release	Permanently powers door control module in the front left door.
f14
f15
f16	7.5A	Stop signal switch	If this fuse is blown, the gearshift will not move out of the park position.
f17	7.5A	Seat belt locking system
f18	5A	Telephone systems/emergency call
f19	5A	Seat belt pre-tensioner
f20
f21
f22	7.5A (15A Japan)	Navigation system	Permanently powers COMAND-APS.
f23	7.5A	CD changer; TV/Rear TV
f24	20A	Car audio system	Permanently powers MOST Audio Gateway.
f25	25A	Sound system
f26
f27

Relays

No.	Description	Comment
A	Wiper heating, end position	A0025421319
B	Binding post 15	A0025421319
C	Binding post 15R	A0025421319
D	Steering column jacket horizontal 1	A0025421419
E	Steering column jacket horizontal 2	A0025421419
F	Recirculating pump	A0025421319
G	Wiper speed 1 / 2	A0025421419
H	Wiper ON / OFF	A0025421419
I	Steering column jacket vertical 1	A0025421419
J	Steering column jacket vertical 2	A0025421419

Right fuse box (F1/1)

Located in engine compartment right.

Fuses

No.	Rating	Function	Comment
f28	15A	Fanfare horns
f29	20A	Gasoline Engine: Engine Emergency stop; Gasoline Engine: Engine management unit
f30	20A	Gasoline Engine: Engine fan; Gasoline Engine: Engine Emergency stop; Gasoline Engine: Engine management unit
f31	40A
f32	40A	Air suspension; Air suspension compressor	Powers Airmatic compressor through 'O' relay.
f33	40A	Automatic temperature control; Blower motor AC
f34	10A	ESP
f35	15A	Steering wheel heating
f36	7.5A	Distronic
f37	15A	Transmission control
f38	5A	Trunk interior non-locking switch
f39	40A	Adjustable mirror, right; Automatic dimming exterior mirror; Entrance lights; Exterior mirror indicators, left/right; Folding exterior mirror; Front passenger seat heating; Heated mirror; Passenger seat adjustment; Power locking; Power window, passenger seat	Powers door control module in the front right door.
f40	10A	Head light range adjustment
f41	20A	Auxiliary heating; Heater booster
f42	20A
f43	25A	Diesel engine: Engine Emergency Stop; Diesel engine: Engine management unit
f44	10A	Diesel engine: Engine fan; Diesel engine: Engine Emergency stop; Diesel engine: Engine management unit
f45
f46	5A	ABC suspension; Air suspension	Terminal 87 to Airmatic control unit.
f47	10A	Automatic temperature control
f48
f49	15A	Ignition coils

Relays

No.	Description	Comment
K	Motronic / Chassis	A0025421319
L	Starter	Activates starter. A0025422319
M	Diesel control system
N	Secondary air pump	A0025421319
O	Air suspension	Activates Airmatic compressor. A0025421319
P	Horn	A0025421119

Fuses for 12 Cylinder AMG Only

Fuses for 12 Cylinder AMG Only

No.	Rating	Function	Comment
f87	20A	AMG (12 cylinder) Engine fan; AMG (12 cylinder) Engine Emergency Stop; AMG (12 cylinder) Engine management unit
f88	20A	AMG (12 cylinder) Engine Emergency stop; AMG (12 cylinder) Engine management unit
f89
f90	10A
f91	10A	AMG (12 cylinder) Fuel pump

Relays for 12 Cylinder AMG Only

No.	Description	Comment
V	Motronic
W	Coolant pump charge air
X	Fuel pump AMG

Rear fuse and relay module (K40/5)

Located in cabin under right rear seat.

Fuses

No.	Rating	Function	Comment
f50	10A	Rear window blind
f51	5A	Anti-theft alarm system
f52	30A	Fuel pump
f53	50A	Rear window defroster
f54	10A	Trailer coupling
f55	25A	Trailer coupling; Trailer power supply
f56	30A	Trailer coupling
f57	25A	Remote closing and locking trunk lid
f58	7.5A	Keyless Go
f59	30A	Taxi
f60	7.5A	Antenna booster; Electronic toll collection	Permanently powers navigation unit in trunk.
f61	7.5A	Telephone systems/emergency call; Voice control system/Linguatronics	Permanently powers TV tuner in trunk.
f62	20A	Central locking; Power locking; Rear head release; Rear head restraint adjustment; Remote closing and locking trunk lid; Remote trunk lid release; Trunk interior non-locking switch
f63	30A	Interactive seat
f64	25A	Driver seat adjustment; Driver seat heating; Driver seat ventilation; Seat belt comfort fit system
f65
f66	25A	Front passenger seat heating; Front passenger seat ventilation; Passenger seat adjustment; Seat belt comfort fit system
f67	25A	Rear seat adjustment; Rear seat heating; Rear seat ventilation
f68	15A	Rear air conditioning
f69	15A	Rear air conditioning
f70	10A	Tyre (tire) pressure monitoring system
f71	40A	Seat belt pre-tensioner
f72	40A	Cigarette lighter rear left; Entrance lights; Power locking; Power window rear left; Rear head restraint adjustment; Rear seat adjustment; Rear seat heating	Permanently powers door control module in the rear left door.
f73	40A	Seat belt pre-tensioner
f74	40A	Cigarette lighter rear right; Entrance lights; Power locking; Power window rear right; Rear head restraint adjustment; Rear seat adjustment; Rear seat heating	Permanently powers door control module in the rear right door.
f75	10A	Parktronic system
f76	15A	Cool box
f77	40A	Automatic dimming interior mirror; Dome lamp; Garage door opener; Interior mirror adjuster; Interior motion sensor; Makeup mirror; Rain/Driving light sensor; Reading lamps; Sliding/tilting sunroof

Relays

No.	Description	Comment
Q	Rear blind
R	Tow-away protection EDW
S	Binding post 15
T	Fuel pump
U	Rear window heater

Cockpit fuse box (F3)

The fuse box is located in cabin dashboard on the passenger side (right on LHD vehicles and left on RHD vehicles).

These images show fuse box location in left-hand drive vehicles.

The next image shows fuse box designations in right-hand drive vehicles.

Fuses

No.	Rating	Function	Comment
f78	7.5A	Adjustable steering column; Anti-theft alarm system; Cruise control; Engine management unit; Ignition lock; Steering wheel heating; Steering column module; Windscreen wipers
f79	5A	Instrument cluster	Powered at all times
f80	10A	Adjustable mirror, left; Adjustable mirror, right; Anti-theft alarm system; Auxiliary heating; Distronic; ESP; Hazard warning system; Heater booster; Parktronic system; Rear head release; Rear head restraint adjustment; Rear window blind
f81	10A	Diagnostic socket
f82	10A	Automatic temperature control; Rear window defroster
f83	10A	Central control unit
f84	5A	Diagnostic socket; Instrument cluster	Powered in run or start
f85	5A	Instrument cluster
f86	15A	Cigarette lighter front

Fuse Charts

Original fuse charts and fuse booklets in compact printable form are available below.

The fuse chart along with fuse removing tool and spare fuses are stored in tool box of the spare wheel well.

Part No. Applicable A0005451400 To Date: 30/06/2001, Replaced by: A0005451500 A0005451500 (compact chart) To Date: 30/06/2001 A0005451600 (compact chart) From Date: 30/06/2001 To Date: 30/09/2002 A0005451700 (compact chart) From Date: 30/09/2002 To Date: 30/09/2003 A0005451800 (compact chart) From Date: 28/10/2003

Spare fuses in tool box.

W220 Update model searchable, both alphabetically and numerically, fuse charts in compact printable form are available here.

File:W220 Fuse Ratings Locations and Consuming Units Version 02.pdf

Electronic Fuses

The following electronic consumers are electronically fused by SAM (Signal Acquisition / Actuation Module): Dipped beam headlamp, left/right; Fog lamp, front left/right; Front side light left/right; Hazard warning system; Main beam headlamp left/right; Rear fog lamp; Rear side lamp left/right; Registration plate lighting; Reversing lamp; Trunk light; Turn indicators.

Prefuses

In addition, there are several large fuses, 100 amp or so, sometimes called "pre-fuses" that supply power directly from the battery via large red wires to the SAMs and the fuse boxes attached to them. The "pre-fuses" are not shown on the fuse diagrams. If these are shorted, the fuse and the block that contains it must be replaced. The 100 amp fuses are not available separately.

There are two prefuse boxes in W220. X4/10 (underneath the passenger footwell carpets) and X4/22 (trunk right).

X4/10

Front prefuse box X4/10 (Circuit 30 and 61 terminal block and fuse box) is located underneath the passenger footwell carpets.

It has a high-capacity capacitor installed in it, so be careful with tools in the area. The capacitor is purely for smoothing voltage spikes to vital electronics.

Front footwell with carpets removed.

Front prefuse box.

Front prefuse box (X4/10) opened.

Front prefuse box (X4/10).

Front prefuse box (X4/10) opened.

It contains 3 fuses:

• X4/10f1 - 150A
  • Left front fuse and relay module
  • Engine fuse and relay box - Valid for S55 AMG, S65 AMG, and engine 275
• X4/10f2 - 60A
  • Electronic ignition switch (EIS) [EZS] control unit - 60A
• X4/10f3 - 150A
  • Right front fuse box and relay module
  • Alternator (B+)
  • Engine and AC electric suction fan with integrated control

Thick red wire goes to battery (unfused). According to wiring diagram, starter's B+ wire is connected to battery through this prefuse (unfused).

X4/22

Rear prefuse box X4/22 (Terminal block and fuse box (circuit 30Z)) is located behind trunk lining on the right side.

It contains 2 fuses:

• X4/22f1 - 60A
• X4/22f2 - 100A

Rear prefuse box under trunk lining.

Rear prefuse box (X4/22) opened.

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Issues

Corrosion

A common issue with W220 Fuses is corrosion on the Fuse Link terminals and the Fuse Box terminals.

The corrosion creates a weak connection and adds resistance into the circuit. Then any current passing through the circuit creates heat at the resistance. Even a small current through the circuit will generate power and hence heat as per Power = Current squared times Resistance.

Notice double the current you get four times the power! So when you get a current increase due to a failure down stream the heat rockets up dramatically and if sufficient starts to melt plastic leading to catastrophic failure.

Many w220 owners have experienced this with ACC Blower Fuse f33 located in Engine Compartment Right Front Fuse and Relay Module (K40/7). The following images show a completely failed 40A fuse and corroded ones and a melted Fuse and Relay Box.

The solution used by some owners with complete f33 failure is to route the power to the blower outside the fuse box even before the problem occurs. At a minimum, everyone should replace the 40 amp MAXI fuse f33 with a new and di-electric greased one. While you are at it why not grease them all.

Permatex 22058 Dielectric Tune-Up Grease.

For further information on DIY diagnosing the problem with f33 see Blower.