Fuses and relays Mercedes A-Class (W168; 1997 - 2004)

The first generation of the A-Class was introduced in autumn 1997. The Mercedes W168 has become a very unusual model in the company's lineup: in addition to an unusually short body, it was equipped with front-wheel drive. Another feature was the frontal impact absorption system (the so-called "sandwich"). In this material, we will analyze in detail the Mercedes fuse circuits in the back of the W168 1st generation A-class ( A140, A150, A160, A170, A180, A190, A200 and A210) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004 release.

Here you will find the locations and diagrams of the fuse blocks. Separately, we note the elements responsible for the cigarette lighter and fuel pump.

In the passenger compartment

Primary fuse box

Located on the front passenger side under a cover in the footwell. 

General view of the main block.

Main compartment fuse box diagram
No.	Description	A
1	fuel tank vent valve	20, 10 diesel
	fan relay
	fuel injection control unit
	idle speed control unit
	EGR valve
	lambda probe heater 1
	lambda probe heater 2
	diagnostic connector
	[tempomat]
	relay and boost valve. USA models
	fuel cutoff valve
	fan relay diesel power control unit	10 (diesel)
	diaphragm valve
	throttle valve
	EGR valve
	catalyst temperature sensor
2	ignition coil engine control unit	25 (diesel)
	fuel injectors
	fuel pump fuse
	electronic accelerator
	starter blocking and shutdown relay
3	radiator blower [with air conditioner]	30, 40
4	engine control module	7.5
5	automatic clutch	40
6	fuel pump relay	30
7	car lighting module	40
8	starter blocking and shutdown relay	30
9	cleaner motor	40
10	electric sunroof	40
	rear window wiper	20
11	steering column switch:	15
	- glass cleaner
	- sound signal
	- washer pump
	- radio navigator
	- cigarette lighter fuse mercedes w168
12	socket in the trunk radio, glove compartment light, CD changer	30
13	front door window lifter	30
	windows for all doors	7.5
14	instrument panel (clock) purifier and washer relay [mobile phone]	10
15	airbag unit	10
	child seat recognition unit
	[side airbag sensor]
16	exterior mirror drive and mirror heater [parking assist]	15
17	horn	15
18	dashboard	10
	transponder and remote control signal receiver
	electronic engine control unit relay
19	towing hitch	30
20		15
21		15
22	audio system	25
23	No
24	No
25	No
26	No
27	No
28	dashboard	10
	[windows]
29	central locking	15
	seat position recognition unit
30	transponder and signal receiver from the remote control	7.5
	electronic instrument panel
31	heated rear window	25
32	[mobile phone]	15
	[radio receiver or radio navigation system]
	[CD changer]
	interior lamps
33	window lifters	30
34	fuel filter heater or (supercharged US models	30/40
35	[burglar alarm control unit]	10
	2x relays of light and sound signaling
36	heated front seats	25
37	[program selector]	10
	coolant heater relay
38	air conditioning compressor	10
	air mixing flap motor
	interior air temperature sensor
	washer jet heater
39	lighting module	7.5
	reversing light
40	brake lights	10
41	air conditioning compressor, diagnostic connector	10
42	window lifters	30
43	ESP brake light switch	15
44	transmission control unit or automatic clutch	10
45	interior heater or [air conditioner] fan	30
46	onboard network	80
47	power steering pump	60
48	preheating control unit.	60
	Diesel vehicles
No.	Relay assignment
K7	Mercedes W168 fuel pump relay
K8	fuel system control unit and ignition relay ESP / VGS or ESP / automatic transmission.
K9	VGS = 6nok gearbox control
K10	heated rear window

Additional fuse box

An additional block is located near the headlight switches on the side of the dashboard.

Diagram
No.	Appointment	A
1	Left headlight - low beam	7.5
2	Right headlight - low beam	7.5
3	Headlamp-high beam, headlamp high beam indicator	15
4	Front Left / Rear Left Lamps	7.5
5	Front / rear rightparking lights, license plate lights, dashboard lights	15
6	Fog lights and lights	15

In the engine compartment

The relay module box is located on the right side under a plastic cover. To access its elements, it is necessary to unscrew the three fastening screws, squeeze the latches and remove the cover.

Access example.

Diagram
No.	Description
1	Windshield washer pump
2	Horn
3	Prohibition of inclusion of stoplights
4	Start inhibit relay
5	cooling fan
6	ABS / ESP pump
7	Exhaust air pump (petrol)

General arrangement

Location of electrical equipment.

No.	Component
1	Air conditioner control module - in the heater control panel
2	Antenna Signal Booster
3	Anti-theft control module - interior lamps
4	Vehicle tilt sensor (anti-theft system) - in the anti-theft system control unit
5	Anti-theft system horn
6	Volume change sensors (anti-theft system) - in the anti-theft system control unit
7	Anti-theft alarm control unit - in the immobilizer control unit
9	Additional heater remote control receiver
10	Battery legroom, passenger side
12	Clutch control module
13	Diagnostic connector (DLC)
14	Power window control module - in the front power window control panel
15	Left front power window control module - in the power window motor
16	Rear left power window control module - in the power window motor
17	Right front power window control module - in the power window motor
18	Rear Right Power Window Control Module - in the power window motor
19	Fuse box
20	Main fuse / relay box, footwell
21	Relay box, engine compartment
22	Horn - behind the front bumper
23	immobilizer control unit
24	Immobilizer ring antenna - near the ignition switch
26	Lighting control module-in head light switch
27	Multifunctional control unit - functions: central locking, direction indicators, sunroof - in the instrument cluster
28	Navigation control unit - in audio unit
29	Air temperature sensor
30	Parktronic control unit
31	Rain sensor - inside rearview mirror
32	Seat heating control unit - in switch block
33	left side impact sensor
34	right side impact sensor
35	SRS module
36	Telephone connection module
37	Telephone interface control unit
39	Relay for intermittent operation of the windshield wiper - windshield wiper motor