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

alfa romeo 166 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)

alfa romeo 166 fuse location 1998 2003
alfa romeo 166 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)

alfa romeo 166 fuse location 2003 2007
alfa romeo 166 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

alfa romeo 166 1998 2003 passenger compartment fuse box
alfa romeo 166 1998 2003 passenger compartment fuse box

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

alfa romeo 166 1998 2003 passenger compartment fuse box 2
alfa romeo 166 1998 2003 passenger compartment fuse box 2
alfa romeo 166 1998 2003 passenger compartment fuse box 02
alfa romeo 166 1998 2003 passenger compartment fuse box 02
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)

alfa romeo 166 1998 2003 engine compartment fuse box
alfa romeo 166 1998 2003 engine compartment fuse box
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)

alfa romeo 166 2003 2007 luggage compartment fuse box
alfa romeo 166 2003 2007 luggage compartment fuse box
alfa romeo 166 2003 2007 luggage compartment fuse box 2
alfa romeo 166 2003 2007 luggage compartment fuse box 2
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)

alfa romeo 166 2003 2007 engine compartment fuse box
alfa romeo 166 2003 2007 engine compartment fuse box
alfa romeo 166 2003 2007 engine compartment fuse box 2
alfa romeo 166 2003 2007 engine compartment fuse box 2
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)

alfa romeo 166 2003 2007 engine compartment fuse box 02
alfa romeo 166 2003 2007 engine compartment fuse box 02
No. Amps Assignment/Designation
4 70A CPL
5 70A CVB
6
7 150A CVM

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

alfa romeo 166 2003 2007 relays
alfa romeo 166 2003 2007 relays

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

alfa romeo 166 2003 2007 relays 2
alfa romeo 166 2003 2007 relays 2

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.