The wiring harness The ammeter Engine oil
The wipers LED instr. light LED Repeaters and lights
The Wiring Harness        How to replace it on your Duetto


The wiring harness          Do it yourself        
         By Wille R. 

You may replace your wiring harness on your Duetto, it is not that tricky after all. New wiring harnesses/looms cost a lot of money but can be done by yourself. Here is the wiring chart made by Papajam. Thanks.

It is not easy to find the correct colour coded wires and connectors, but try this well known UK based company. 

Or this UK vendor as well. so the choice is up to you.

You will need wires in different colours, they all are square 1mm as original. Go for the Single core PVC Thin wall cables as they are the latest version and much lighter and smoother than the old PVC wires. Some wires, red on the wiring chart are thicker, but you will see when you start which they are. 

The chart below is what I used for my Euro 1750 Veloce Duetto. Mine has a fuse box with ten fuses as in the diagram. The US will need additional wires and colours. Just add them after checking what your Duetto has. The Spica and side markers for instance. The wiring charts for those are at Pls see page 114 and 115 or straight to the wiring chart as a Pdf. There are charts for the other 105 Alfas too, 1750 Berlina, the Bertone and of course the Duetto.  

Wires. All wires are square 1mm apart from some of the red. Please see wiring chart. Here is my estimation about the wires and connectors.

  Colour Meters  


12m 1,0mm
6m 2,5mm
3m 4.0mm
Battery (+) various supplies, brake lights often related to ignition on. Some are bigger than square 1mm, you will need 2,5mm for the beams. The main supply from the starter to the terminal
2 Black 6m  Starter (-) 2,5mm
3 Blue 8m Turn signal right 
4 Blue/black 11m Turn signal left 
5 Yellow 10m Parking ligth front left,  number plate, tail light right
6 Yellow/black 9 m Parking  light front right, number plate, tail light left
7 Green 2m Main beam right
8 Green/black 5m Main beam left
9 Brown 3m Coolant temp
10 White 7m Brake lights + switch/wipers
11 Purple 7m Horn +  fuel tank
12 Grey = slater 2m Dipped beam right
13 Grey/black 5m Dipped beam left
14 Red/black 2m Oil pressure sender
15 White/black 3m Foot wiper switch 
16 Pink 3m Alternator, instruments
17 Pink 2m 2,5mm Relay to horn

Connectors etc. 

8 ways x 2 For the wires going to the rear units in trunk
Under the steering column, light/Turn control
x 1
x 1
4 ways x 6  Headlights beams,
Wiper motor 
Foot wiper switch (if you have one) 
Rear tail/brake lights 
x 2 left and  right
x 2 left and right 
2 ways x 4 Wiper
Trunk- rear license lights
Turn signals
x 1
x 1
x 2 left and right
Sleving to protect the wires. PVC or Twist wrapped. Or you may use electric tape as original or conduit sleeves. It's up to you. The vendors in the article have everything you need..


You will need at least wires according to the chart above. The list above is just what I got and used. The good thing is that the wires are not expensive. The wiring harness runs from the fuse box to the A-pillar and tail loom runs over the left sill, then the B-pillar into to the trunk, left side. On the way there is an eight ways connector.  The fuel tank sender is on top of the tank. The licence plate lamps are running inside the boot lid, left side.

Oh, the fuse box has a fuse #1 that serves the cig. lighter and cortesy light on the mirror. If you don't use these, it is a good idea to connect the brake lights through that fuse.

The wires continue to the left rear tail/brake light, then the connector with four ways takes care of the light assembly incl. the repeator/turn signal. The right rear light unit uses a four ways connector too. 

The total length you will need is in the chart above. The head lights wires runs from the fuse box into the engine bay, carb side and then over the radiator. The front repeaters/turn signals and parking lights do so as well. 

Four meters should be enough but as the wires have a modest price, get some extra. Behind the dash, it looks like a terrible mess, but if you replace the wires one by one using the same colour you can do it. And save a lot of money and have a good time with the colour new wires. 

The wires for the headlights an turn signals and parking lights go through the firewall right side, close to the fuse box. 

Start at the fuse box and place the new wires along with the old ones to get the proper length and position. Then when you are ready cut and crimp the connectors and so on. New wires are far better and have better plastic cover.

Cordially     Wille R.