Alfa Romeo 166 fuse box and relay Diagrams (1998-2007)

Alfa Romeo 166 is a flagship sedan manufactured by Italian automaker Alfa Romeo from 1998 to 2007. The vehicle is designed by Walter de Silva and is built on the Type Three platform, shared with the Lancia Kappa and the Fiat Croma. The Alfa Romeo 166 is a successor to the 164 models, and it is offered with a range of engines and trim levels to suit different customer preferences.

One important aspect of the Alfa Romeo 166 is its electrical system, which includes a fuse box and relay that play critical roles in the car’s operation. In this article, we will explore the different electrical components of the Alfa Romeo 166, including the fuse box and relay, and how they contribute to the car’s functionality.

Alfa Romeo 166 Electrical System

The Alfa Romeo 166 features an advanced electrical system that includes a fuse box and relay. The fuse box contains fuses that protect different circuits in the car from overloading or short-circuiting. The fuses in the Alfa Romeo 166 are color-coded, and each color represents a different amperage rating. A blown fuse can cause a specific system to stop working, and it is essential to replace the faulty fuse with a new one of the same amperage rating.

The relay, on the other hand, is an electrical switch that controls the operation of various systems in the car, such as the fuel pump, headlights, and windshield wipers. The relay works by receiving a signal from a switch or sensor and then using an electromagnet to open or close a circuit. A faulty relay can cause various systems to malfunction or stop working, and it is crucial to replace a bad relay promptly. The fuse box and relay are located in the engine compartment, and their location may vary slightly depending on the year and model of the Alfa Romeo 166.

MUST READ: DYI – How to Check Car Fuses?

(1998-2007) Alfa Romeo 166 fuse box and relay with Diagram

Fuse Location (1998-2003)

This model is fitted with two junction units: a main junction unit (1) located underneath the dashboard to the left of the steering column and an auxiliary junction unit (2) positioned in the engine compartment.

Fuse Location (2003-2007)

This model is fitted with three junction units: one (1) located underneath the dashboard to the left of the steering column, one (2) located in the engine compartment and a third (3) in the boot. In addition, the power supplies coming from the battery are protected by MAXIFUSES located on the actual battery.

Passenger Compartment Fuse Box

Access to it is gained slackening the knob (A) and lowering the panel (B).

No.	Amps	Assignment/Designation
1	15A	Brake Lights, IGE Control Unit, Brake Depressed Light Control Signal, Control Panel, Direction Indicators (Steering Column Switch Unit), Exterior Lights Control
2	10A	Air Bag Control Unit, Gearshift Lever
3	5A	’03-’07: Sun Roof, Rear Socket, Seats
	?	Fuel Pump
4	15A	Radio
5	10A	Mobile Phone, Glove Compartment Light, Cruise Control, Gear Lever Panel (CAE), Light Dimmer, Door Opening Receiver, Heated, Fold-Down Door Mirrors, Antitheft Control Unit, Switch On Console (C.M.), Compressor Relay Coil, Symbols (Switches/Buttons), I.C.S. System, Sound System Controls on Steering Wheel
6	7.5A	’03-’07: Control Panel, Control Lighting, Headlights and Headlight Position Sensor (Gas Discharge Headlights), I.C.S. System
	5A	’98-’03: Climate Control Fan Relay Coil
7	10A	Front Current Socket (Cigar Lighter), I.C.S. System
8	10A	Direction Indicators and Hazard Warning Lights, Right Side Lights
9	5A	’03-’07: Control Lighting, Brake Lights Switch, IGE Control Unit, ABS
	5A	’98-’03: Electrochromic Mirror, Rain Sensor, Preparation for Telepass, Relay Coil for Seat Heat Pad Control, Signal to Front Electric Window Control Unit, Signal to Rear Electric Window Control Unit, Climate System Controls, Rear Electric Window Switch Inhibition Light
10	5A	CAE Control Unit, Electronic Automatic Gearbox (Control Unit, Sensors and Gearshift Lever)
11	15A	’03-’07: IGE Control Unit, Headlight Spot
	20A	’98-’03: IGE Control Unit
12	20A	Headlamp Washer
13	10A	’03-’07: Sun Roof, ABI Control Unit, Electronic Automatic Gearbox, Reversing Lights (only Versions with Manual Gearbox)
	15A	’98-’03: Sun Roof, Reversing Light Signal for Electrochromic Mirror
14	25A	Windscreen Wash/Wiper
15	10A	’03-’07: IGE Control Unit, Rear Light Units
	25A	’98-’03: Motor for Right/Left Front Electric Windows
16	5A	Alfa Romeo Code System, Electronic Injection System, Engine Cooling Control Unit, Compressor Relay, Electronic Automatic Gearbox, Fuel Pump Relay Coil (Engine Bay Box)
17	10A	’03-’07: IGE Control Unit, Left Side Lights
	10A	’98-’03: Transmission Lever Panel (CAE), Passegner Compartment Courtesy Light, Door Lights, Boot Light, Glove Compartment Light, Light Dimmer, Climate Control System Control Unit, Antitheft Control Unit, Remote Control Receiver, Diagnostic Socket
18	5A	Instrument Panel, I.C.S. System, Preparation for Mobile Phone, EOBD System (Diagnostic Socket), Navigator
19	5A	’03-’07: Climate Control System Control Unit
	25A	’98-’03: Central Locking Motor, Additional Current Socket
20	5A	Alfa Romeo Code System- Injection (Petrol)
Relay
R1	Ignition Discharge
R2	’98-’03: Direction Indicators/Hazard Warning Lights Flasher
R3	Headlamp Washer Intermittent

Engine Compartment Fuse Box (1998-2003)

No.	Amps	Assignment/Designation
1	10A	Right Main Beam Headlamp
2	10A	Left Main Beam Headlamp
3	15A	Fog Light
4	15A	Horns
5	10A	Air Conditioning Compressor
6	10A	Left Dipped Headlamp
7	10A	Right Dipped Headlamp
8	50A	High Speed Radiator Fan
9	50A	Low Speed Radiator Fan
Relay
R1	Dipped Beam Headlamps
R2	Horns
R3	Air Conditioning Compressor
R4	Main Beam Headlamps
R5	Fog Light
R6	High Speed Radiator Fan
R7	Low Speed Radiator Fan

Additional Fuses (1998-2003)

No.	Amps	Assignment/Designation
1	80A	JTD: Plug Preheating Control Unit
2	30A	Ignition Coils, Fuel Injection Main Relay, Fuel Pump Relay, Engine Management Control Unit, Fuel Injection Control Unit Supply Relay, Fuel Injection Services Supply Fuse
3	30A	JTD: Additional Heater
4	15A	JTD: Diesel Pre-Heating
5	30A	Starter
7	60A	ABS
8	40A	’01-’03: Radiator Fan (2.4 JTD 10v – ???)
9	30A	Vehicle Interior Fan
10	5A	CAE Supply
11	10A	ABS
12	7.5A	JTD: Engine Management Control Unit
13	20A	’02-’03: Cigar Lighter

Luggage Compartment Fuses (1998-2003)

No.	Amps	Assignment/Designation
1	40A	Heated Rear Window
2	25A	Fuel Flap Opening
3	20A	Boot Opening
4	30A	Left Seat Adjustment
5	20A	Seat Heating
6	30A	Right Seat Adjustment
7	15A	Trailer
8	25A	Rear Electric Windows
near with Battery
–	125A	Main Fuse
	150A	’99-03 (2.4 JTD 6M): Main Fuse
–	60A	Luggage Fuses
ACC	30A	Ignition Switch
Centr	60A	Fuse: “8”, “10”, “11”, “12”, “15”, “17”, “18”, “19”, “20”, Ignition Discharge Relay, Vehicle Interior Fan Fuse
–	15A	Radio Amplifier

Luggage Compartment Fuse Box (2003-2007)

No.	Amps	Assignment/Designation
54	25A	HIFI Amplifier
55	20A	Sun-Roof
56	20A	Driver’s (LH) Side Front Window
57	10A	Driver’s (LH) Heated Seat
58	–	–
59	7.5A	Mirror Demist
60	20A	Passenger (RH) Side Front Window
	20A	Rear Current Socket
61	20A	Left Rear Electric Window
62	20A	Right Rear Electric Window
63	20A	Central Locking, Boot Release
64	30A	Heated Rear Window
65	10A	JTD: Additional Heater
66	10A	Anti-Theft Device and Light Blinker, Diretction Indicators, Trailer Presetting
67	10A	Passenger (RH) Heated Seat
68	15A	Windscreen Demisting
	20A	Passenger (RH) Side Front Window
69	20A	Rear Current Socket
	15A	Windscreen Heating
77	30A	Driver’s (LH) Seat Movement
78	10A	Interior Lights, Rain Sensor, Mirror Adjustment, Seat Warming Control Light, Sun Vision Lights, Alarm System Control Unit, Electrochromic Driving Mirror, Parking Sensors Control Unit, Remote Control Receiver
79	30A	Passenger (RH) Seat Movement
80	–	–
Relay
R21	Sun Roof, Rear Socket
R22	Windscreen and Mirror Demisting
R23	Heated Rear Window
R24	Ignition Discharge
R25	Climate Control System Control Unit
R26	Lights Blinker

Engine Compartment Fuse Box (2003-2007)

No.	Amps	Assignment/Designation
1	50A	JTD: Glow Plugs
	60A	JTD: Glow Plugs
2	40A	ABS
3	20A	Ignition Switch
	30A	Starter Motor
4	40A	ABS
5	10A	CAE Ignition Lock
	20A	Electronic Automatic Gearbox (3.0 V6 24V Sportronic Version)
6	30A	Engine Cooling Fan (Low Speed)
	40A	Engine Cooling Fan (Low Speed)
7	60A	Engine Cooling Fan (High Speed)
8	30A	Climate Control Fan
9	15A	Electronic Automatic Gearbox – Sportronic Versions (Control Unit, Sensors and Gearshift Lever)
10	15A	Horns
11	15A	Electronic Injection Control Unit, Various Auxiliary Services I.E., Diesel Filter (JTD)
14	15A	Right Main Beam Headlamp
15	15A	Left Main Beam Headlamp, Headlamp Alignment
16	–	–
17	10A	Electronic Injection Control Unit
18	7.5A	Engine Control Unit, I.E. Services, CAE
19	7.5A	Conditioner Compressor
20	30A	JTD: Diesel Filter Heating
21	15A	Fuel Pump
22	20A	Electronic Injection Control Unit
23	20A	JTD: Additional Heater
24	–	–
30	15A	Front Fog Lights
Relay
R2	High Beam
R3	Horn
R5	Compressor
R6	Radiator Fan 1st Speed
R7	Radiator Fan 2st Speed
R8	Climate Control System
R9	Fuel Injection Main
R10	Fuel Pump
R14	Fog Lamp
R17	CAE
R19	Heated Diesel Filter
R20	Starter Inhibitor

Engine Compartment Fuse Box No.2 (2003-2007)

No.	Amps	Assignment/Designation
4	70A	CPL
5	70A	CVB
6	–
7	150A	CVM

Additional Heater Relay, Cooling Fan Relay (JTD – 2003-2007)

To gain access to relays on the bracket set behind the left headlight, remove the cover (A) after turning the fastening pins (B).

Brown Relay: Additional Heater
Black Relay: Engine Cooling Radiator (High Speed)

Conclusion

The Alfa Romeo 166 is an impressive sedan that offers exceptional driving dynamics, premium features, and advanced technology. The car’s electrical system, including the fuse box and relay, plays a critical role in the vehicle’s operation and performance. Understanding how these components work and how to troubleshoot them can help keep the Alfa Romeo 166 running smoothly and prevent unnecessary breakdowns. Regular maintenance and inspections of the electrical system are essential to ensure the reliability and longevity of the Alfa Romeo 166.