Fuses: Difference between revisions

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This page describes fuse boxes, fuses and relays as of W220 [[facelift]] vehicles (from 30/09/2002).
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 form are available for download in the section below.
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.
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.


==In Engine Compartment Left==
==Fuse Ratings and Colour Codes==
{| class="wikitable"
|-
! 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.
{|
{|
|[[File:W220_fuse_box_in_engine_compartment.png|300px]]
|[[File:W220_fuse_box_in_engine_compartment.png|300px]]
|[[File:220170fs_2.jpg|300px]]
|[[File:220170fs_2.jpg|300px]]
|[[File:220170fs_3.jpg|300px]]
|[[File:220170fs_3.jpg|300px]]
|[[File:Fuses 1 to 27 and Relay Box in Engine Compartment Left.jpg|300px]]
|}
|}


Line 36: Line 63:
| f8 || || ||
| f8 || || ||
|-
|-
| f9 || 20A || ABC suspension; Air suspension||
| f9 || 20A || ABC suspension; Air suspension|| Permanently powers [[Airmatic]] control module.
|-
|-
| f10 || 15A || Windshield washer system||
| f10 || 15A || Windshield washer system||
Line 50: Line 77:
| f15 || || ||
| f15 || || ||
|-
|-
| f16 || 7.5A || Stop signal switch ||
| 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 ||
| f17 || 7.5A || Seat belt locking system ||
Line 81: Line 108:
! No. !! Description !! Comment
! No. !! Description !! Comment
|-
|-
| A || Wiper heating, end position ||  
| A || Wiper heating, end position || A0025421319
|-
|-
| B || Binding post 15 ||  
| B || Binding post 15 || A0025421319
|-
|-
| C || Binding post 15R ||  
| C || Binding post 15R || A0025421319
|-
|-
| D || Steering column jacket horizontal 1||  
| D || Steering column jacket horizontal 1|| A0025421419
|-
|-
| E || Steering column jacket horizontal 2||  
| E || Steering column jacket horizontal 2|| A0025421419
|-
|-
| F || Recirculating pump ||  
| F || Recirculating pump || A0025421319
|-
|-
| G || Wiper speed 1 / 2||  
| G || Wiper speed 1 / 2|| A0025421419
|-
|-
| H || Wiper ON / OFF ||  
| H || Wiper ON / OFF || A0025421419
|-
|-
| I || Steering column jacket vertical 1||  
| I || Steering column jacket vertical 1|| A0025421419
|-
|-
| J || Steering column jacket vertical 2||  
| J || Steering column jacket vertical 2|| A0025421419
|}
|}


==In Engine Compartment Right==
==Right fuse box (F1/1)==
Located in engine compartment right.


{|
{|
Line 108: Line 136:
|[[File:220175egr_3.jpg|300px]]
|[[File:220175egr_3.jpg|300px]]
|[[File:220170fs_1.jpg|300px]]
|[[File:220170fs_1.jpg|300px]]
|[[File:Fuses 28 to 49 and Relay Box in Engine Compartment Right.jpg|300px]]
|}
|}


Line 123: Line 152:
| f31 || 40A ||  ||
| f31 || 40A ||  ||
|-
|-
| f32 || 40A || Air suspension; <br/>Air suspension compressor ||
| f32 || 40A || Air suspension; <br/>Air suspension compressor || Powers [[Airmatic]] compressor through 'O' relay.
|-
|-
| f33 || 40A || Automatic temperature control; <br/>Blower motor AC  ||
| f33 || 40A || Automatic temperature control; <br/>Blower motor AC  ||
Line 137: Line 166:
| f38 || 5A || Trunk interior non-locking switch ||
| f38 || 5A || Trunk interior non-locking switch ||
|-
|-
| f39 || 40A || Adjustable mirror, right; <br/>Automatic dimming exterior mirror; <br/>Entrance lights; <br/>Exterior mirror indicators, left/right; <br/>Folding exterior mirror; <br/>Front passenger seat heating; <br/>Heated mirror; <br/>Passenger seat adjustment; <br/>Power locking; <br/>Power window, passenger seat || Powers [[door control module]] in the front right door
| f39 || 40A || Adjustable mirror, right; <br/>Automatic dimming exterior mirror; <br/>Entrance lights; <br/>Exterior mirror indicators, left/right; <br/>Folding exterior mirror; <br/>Front passenger seat heating; <br/>Heated mirror; <br/>Passenger seat adjustment; <br/>Power locking; <br/>Power window, passenger seat || Powers [[door control module]] in the front right door.
|-
|-
| f40 || 10A || Head light range adjustment ||
| f40 || 10A || Head light range adjustment ||
Line 151: Line 180:
| f45 || ||  ||
| f45 || ||  ||
|-
|-
| f46 || 5A || ABC suspension; Air suspension ||
| f46 || 5A || ABC suspension; Air suspension || Terminal 87 to [[Airmatic]] control unit.
|-
|-
| f47 || 10A || Automatic temperature control ||
| f47 || 10A || Automatic temperature control ||
Line 165: Line 194:
! No. !! Description !! Comment
! No. !! Description !! Comment
|-
|-
| K || Motronic / Chassis ||  
| K || Motronic / Chassis || A0025421319
|-
|-
| L || Starter || Activates [[starter]]
| L || Starter || Activates [[starter]]. A0025422319
|-
|-
| M || Diesel control system ||  
| M || Diesel control system ||  
|-
|-
| N || Secondary air pump ||  
| N || Secondary air pump || A0025421319
|-
|-
| O || Air suspension || Activates [[airmatic]] compressor
| O || Air suspension || Activates [[Airmatic]] compressor. A0025421319
|-
|-
| P || Horn ||  
| P || Horn || A0025421119
|}
|}
Fuses for 12 Cylinder AMG Only
[[File:Fuses 87 to 91 and Relays in Engine Compartment Front, Right.jpg|500px]]


{| class="wikitable"  
{| class="wikitable"  
Line 206: Line 239:
|}
|}


==In Cabin Under Right Rear Seat==
==Rear fuse and relay module (K40/5)==
Located in cabin under right rear seat.
{|
{|
|[[File:W220_fuse_box_in_the_rear_passenger_compartment.png|300px]]
|[[File:W220_fuse_box_in_the_rear_passenger_compartment.png|300px]]
Line 291: Line 325:
|}
|}


==In Cabin Dashboard Fuse Box==
==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).


The fuse box is located 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 images show fuse box location in left-hand drive vehicles.


{|
{|
Line 300: Line 334:
|[[File:220170db_1.jpg|300px]]
|[[File:220170db_1.jpg|300px]]
|[[File:220175cp_100_1.jpg|300px]]
|[[File:220175cp_100_1.jpg|300px]]
|}
The next image shows fuse box designations in right-hand drive vehicles.
{|
|[[File:Fuses 78 to 86 Cockpit Dashboard.jpg|500px]]
|}
|}


Line 309: Line 348:
| f78 || 7.5A || Adjustable steering column; <br/>Anti-theft alarm system; <br/>Cruise control; <br/>Engine management unit; <br/>Ignition lock; <br/>Steering wheel heating; <br/>Steering column module; <br/>Windscreen wipers ||
| f78 || 7.5A || Adjustable steering column; <br/>Anti-theft alarm system; <br/>Cruise control; <br/>Engine management unit; <br/>Ignition lock; <br/>Steering wheel heating; <br/>Steering column module; <br/>Windscreen wipers ||
|-
|-
| f79 || 5A || Instrument cluster ||
| f79 || 5A || Instrument cluster || Powered at all times
|-
|-
| f80 || 10A || Adjustable mirror, left; <br/>Adjustable mirror, right; <br/>Anti-theft alarm system; <br/>Auxiliary heating; <br/>Distronic; <br/>ESP;<br/>Hazard warning system; <br/>Heater booster; <br/>Parktronic system; <br/>Rear head release; <br/>Rear head restraint adjustment; <br/>Rear window blind ||
| f80 || 10A || Adjustable mirror, left; <br/>Adjustable mirror, right; <br/>Anti-theft alarm system; <br/>Auxiliary heating; <br/>Distronic; <br/>ESP;<br/>Hazard warning system; <br/>Heater booster; <br/>Parktronic system; <br/>Rear head release; <br/>Rear head restraint adjustment; <br/>Rear window blind ||
Line 319: Line 358:
| f83 || 10A || Central control unit ||
| f83 || 10A || Central control unit ||
|-
|-
| f84 || 5A || Diagnostic socket; <br/>Instrument cluster ||
| f84 || 5A || Diagnostic socket; <br/>Instrument cluster || Powered in run or start
|-
|-
| f85 || 5A || Instrument cluster ||
| f85 || 5A || Instrument cluster || Powered in ACC run or start
|-
|-
| f86 || 15A || Cigarette lighter front ||
| f86 || 15A || Cigarette lighter front ||
Line 329: Line 368:


Original fuse charts and fuse booklets in compact printable form are available below.
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.
The fuse chart along with fuse removing tool and spare fuses are stored in tool box of the spare wheel well.
{|
{|
Line 347: Line 387:
|[[File:W220_fuses_tool_box.jpg|thumb|none|Spare fuses in tool box.]]
|[[File:W220_fuses_tool_box.jpg|thumb|none|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|compact chart]]


== Electronic Fuses ==
== Electronic Fuses ==
Line 358: Line 402:


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


{|
{|
|[[File:220067sw_70.jpg|thumb|none|Front footwell with carpets removed.]]
|[[File:W220_front_prefuse_box_location.jpg|thumb|none|Front footwell with carpets removed.]]
|[[File:220175tr_0.jpg|thumb|none|Front prefuse box.]]
|[[File:220175tr_0.jpg|thumb|none|Front prefuse box.]]
|[[File:W220_front_prefuse_box_opened.jpg|thumb|none|Front prefuse box (X4/10) opened.]]
|[[File:W220_front_prefuse_box_opened.jpg|thumb|none|Front prefuse box (X4/10) opened.]]
|}
|}
{|
|[[File:W220_front_prefuse_box.jpg|thumb|none|Front prefuse box (X4/10).]]
|[[File:W220_front_prefuse_box_opened2.jpg|thumb|none|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


{|
{|
Line 373: Line 451:
|{{#ev:youtube|https://www.youtube.com/watch?v=q0KFPZjErmw|320|left|Location of prefuses and fuses.|frame}}
|{{#ev:youtube|https://www.youtube.com/watch?v=q0KFPZjErmw|320|left|Location of prefuses and fuses.|frame}}
|}
|}
==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.
[[File:W220 corroded 40A fuse links.jpg|400px]][[File:W220 Over Heated Blower Fuse f33.JPG|400px]]
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.
[[File:Permatex_22058_Dielectric_Tune-Up_Grease.JPG|thumb|none|Permatex 22058 Dielectric Tune-Up Grease.]]
For further information on DIY diagnosing the problem with f33 see [[Blower]].

Latest revision as of 21:21, 11 January 2024

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 Powered in ACC run or start
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.
Load video
YouTube
Location of prefuses and fuses.

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.

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