Lambretta Wiring Colours Explained – LI, SX, TV, DL & GP Guide

August 12, 2026

Understanding Lambretta Wiring Colours – A Simple Guide to LI, SX, TV, DL & GP Wiring

If you're restoring a classic Lambretta, one of the jobs that can sometimes cause the most confusion is the wiring.

You open the headset, junction box or rear light and suddenly you're faced with a collection of wires in different colours. Brown, purple, green, black, pink, yellow, red and blue can all be involved, and if the scooter has been rewired or modified over the years, things can become even more confusing. Then sometimes you have things like the SIP Speedos and extra gauges to take into account, it can all get a bit discombobulating!

We regularly get asked questions about Lambretta wiring, so we thought we'd put together this simple guide to help explain some of the common Lambretta wiring colours and what they are normally used for.

This guide covers the popular Lambretta LI, LI Special, TV, SX and DL/GP models, including both battery and non-battery systems.

However, there is one very important thing to remember:

Don't assume a wire is doing a particular job simply because of its colour. Always check the wiring diagram and test the circuit where necessary, we have seen plenty of indian looms with wrong wire colours.

Over the years, Lambrettas have been repaired, restored, rewired and modified, so your scooter may not necessarily follow the original factory wiring exactly.

Why Are Lambretta Wiring Colours So Confusing?

Unlike modern vehicles, which tend to have much more standardised wiring systems, classic Lambrettas have had many different wiring configurations becuase of light switch style and if using ignition switches.

There are differences between:

LI Series 1
LI Series 2
LI Series 3
LI 125 and 150
LI Special
TV Series 2
TV Series 3
SX 150
SX 200
DL
GP
Battery models
Non-battery models
Original looms
Replacement looms
Electronic ignition systems
Modified electrical systems

There can also be differences between Italian-market and export-market scooters (mainly UK imported scooters with a factory type D.C. Battery set up).

For example, some Series 3 LI models use an arrangement where the handlebar light switch controls the lighting, while LI Special, TV, SX and GP models generally use an ignition switch to control the lights, with the handlebar switch handling functions such as high/low beam and the horn.

This is why it is important not to simply connect wires based on colour alone.

The Most Common Lambretta Wiring Colours

Let's look at some of the colours you are most likely to come across when working on a Lambretta.

Green – Ignition / Cut-Out

Green is commonly associated with the ignition circuit and cut-out system.

On many Lambretta wiring systems, the green wire is used for the ignition circuit.

At the headset, the green wire can connect to the ignition switch or cut-out circuit.

The purpose of the circuit is to allow the ignition to be interrupted when the engine needs to be stopped.

On electronic ignition systems, the exact arrangement can differ, so always check the wiring supplied with the ignition system but basically, you can follow the green from the ignition switch right the way to your CDI ignition coil.

Brown – Lighting Feed

Brown is commonly used as a lighting power feed.

On many Series 3 Lambrettas, the brown wire is associated with the main lighting circuit.

For example, technical information for Series 3 LI wiring identifies the brown wire as the feed for the main lights.

Brown wires can therefore often be found:

At the headset
Around the ignition switch
At the light switch
Within the main loom
Around the lighting circuit

However, the exact connection depends on the type of loom and switch being used.

Purple – Side Lights / Lighting Circuit

Purple is another colour commonly found within the Lambretta lighting system.

On some original-style non-battery looms, purple is used for the side or parking light circuit.

For example, a common Series 3 LI non-battery arrangement uses:

Green – ignition
Brown – main lights
Purple – side lights
Black – rear light

This is a good example of why understanding the function of the wire is more important than simply remembering its colour.

On later or electronic looms, the purple wire may be handled differently and if converting to 12v from 6v you need to connect the purple and brown wires together in the headset.

Black – Rear Light / Earth

Black is another colour you'll see frequently.

Depending on the particular loom and component, black can be used for the rear light circuit or an earth connection.

For example, on a common Series 3 LI arrangement, the black wire from the headset supplies the rear light circuit.

However, black can also be used as an earth in some wiring arrangements.

This is a perfect example of why you shouldn't automatically assume what a wire does purely from its colour.

Always check the wiring diagram for the particular loom. The Sticky book has plenty of wiring diagrams at the back of the book.

Pink – Brake Light

Pink is commonly associated with the brake light circuit.

On a Series 3 rear light arrangement, the pink wire is used for the stop-light circuit, you will see a pink wire at the brake light switch.

The brake light switch completes the circuit when the brake is operated, illuminating the brighter element of the rear bulb.

If your brake light isn't working, check:

Brake light switch
Pink wire
Rear light connections
Bulb
Earth connection
Wiring continuity

A poor earth can cause some very strange electrical symptoms, so don't overlook it.

Yellow – Lighting Power

Yellow wires are particularly important when dealing with Lambretta stators and lighting systems.

On various Lambretta electrical systems, yellow wires are used to provide power for the lighting circuit.

The exact arrangement depends on the stator, regulator, loom and whether the scooter is using an original or electronic ignition system.

On certain electronic ignition conversions, for example, the yellow stator wires provide the lighting feed.

Don't assume every yellow wire connects to the same component.

Always follow the wiring instructions supplied with your particular ignition or regulator.

Blue – Headlamp Main Beam

Blue is commonly found around the headlamp and light switch circuit.

On Series 3 LI wiring, the red and blue wires from the light switch are associated with the main headlamp connections.

Depending on the particular model and switch arrangement, blue may therefore be involved with the headlamp beam circuit.

Again, check the wiring diagram rather than relying purely on the colour.

Red – Headlamp Circuit

Red can also be found within the headlamp wiring.

On a Series 3 LI light switch, the red and blue wires are associated with the main headlamp connections.

The exact function can depend on the switch and loom being used.

White – Horn Circuit

White is commonly associated with the horn circuit and earth on some Lambretta wiring systems.

On the Series 3 LI light switch arrangement, white and brown wires are used in the horn circuit.

If you're working on the horn circuit, don't forget to check the earth and the condition of the horn itself.

The Important Difference Between LI and LI Special / TV / SX / GP

This is one of the areas that causes the most confusion.

Not all Series 3 Lambrettas use exactly the same electrical arrangement.

LI 125 / 150 Series 3

On many LI Series 3 models, the handlebar light switch controls the lighting, while the ignition is controlled separately by a cut-out or ignition switch.

Technical information for LI Series 3 models describes the lighting and ignition arrangement separately, again the sticky book will help you get your head around this.

A commonly encountered non-battery loom arrangement has:

Colour	Common Function
Green	Ignition
Brown	Main lights
Purple	Side lights
Black	Rear light

LI Special, TV, SX & GP/DL

The LI Special, TV, SX and GP/DL models generally use a different style of lighting control.

These models commonly have an ignition switch that controls the lights, while the handlebar light switch controls functions such as high/low beam and the horn.

This means you shouldn't automatically wire an LI Special, SX, TV or GP in exactly the same way as a standard LI Series 3. There are 2 different switches you can buy, a 4 position D.C. style which allows a parking light or there's a 3 position non battery A.C. switch.

This distinction is particularly important when fitting:

New wiring looms
New ignition switches
New light switches
Electronic ignition
Replacement headset components

Battery vs Non-Battery Lambrettas

Another major consideration is whether your Lambretta uses a battery or non-battery electrical system.

Non-Battery Systems

Traditional non-battery Lambrettas generally use an AC lighting system supplied from the stator. This is the main choice for most Lambretta owners.

This means the lighting circuit works differently from a modern battery-powered DC system.

A typical non-battery Series 3 LI loom may have four wires at the headset:

Green
Brown
Purple
Black

with the common functions described above.

Battery Systems

Battery-equipped Lambrettas have a different electrical arrangement because the battery provides a source of DC power.

This can affect:

Horn
Brake light
Indicators where fitted
Accessories
Ignition switch
Lighting arrangements
Regulator connections

When replacing a loom, make sure you purchase the correct battery or non-battery loom for your scooter.

Don't assume that because the loom physically fits the frame, it is electrically correct for the scooter.

Electronic Ignition Changes Things

Many Lambrettas have now been upgraded from their original points ignition to an electronic ignition system.

Popular electronic ignition systems can have their own wiring arrangements and regulators.

This means the original wiring colours may not always connect directly to the new ignition system in the same way.

For example, electronic ignition systems can use yellow wires from the stator for lighting power, with the wiring arrangement depending on the particular system and regulator.

Always follow the wiring diagram supplied with the electronic ignition system.

Don't connect an electronic ignition system purely based on the colours of the original stator wiring and don't forget to use the copper earth wires.

What If the Wire Colours Don't Match?

This is something we see regularly.

You may have an original loom in the scooter but a replacement switch.

Or perhaps the scooter has:

A replacement loom
Electronic ignition
Different headset
Different light switch
Modified wiring
Additional accessories
Previous repairs

You might therefore find that the colours don't match exactly.

Don't panic.

The best thing to do is identify the function of each wire.

How to Identify a Wire

If you're unsure what a wire does, a multimeter can be extremely useful.

Before testing anything:

Disconnect the battery and make sure the ignition is switched off.

Use the continuity function on the multimeter to trace a wire through the loom.

You can also follow the wiring diagram from one component to another.

For example:

Brake light not working?

Don't simply assume the pink wire is faulty.

Check the complete circuit:

Brake switch → wiring → rear light → bulb → earth

If the circuit is broken anywhere along that route, the brake light won't work.

Don't Trust an Old Loom

If you're restoring a Lambretta that has been apart for many years, don't automatically assume that the wiring is original. We had a customer in recently that basically rebuilt his engine but found out there was internal damage to his old spanish loom that was home made years ago.

Previous owners may have:

Repaired damaged wires
Changed wire colours
Added connectors
Added accessories
Installed alarms
Changed ignition systems
Changed regulators
Added indicators
Modified lighting
Installed a battery

You may therefore find a scooter that doesn't match the original wiring diagram.

If the loom looks old, damaged or heavily modified, replacing it can often save a huge amount of time and frustration.

Check Your Earth Connections

One of the most overlooked parts of Lambretta electrical systems is the earth. This is also non negotiable when fitting a VAPE ignition, earthing needs to be perfect.

A poor earth can cause:

Dim lights
Flickering lights
Brake light problems
Horn problems
Strange electrical faults
Components working intermittently

Make sure earth points are clean and free from:

Paint
Powder coating
Rust
Dirt
Corrosion

When restoring a Lambretta, a good electrical connection between the component and the frame is essential.

A Simple Lambretta Wiring Colour Reference

Here's a useful quick-reference table.

Remember: these are common functions, not an absolute rule for every Lambretta or replacement loom.

Wire Colour	Common Function
Green	Ignition / cut-out
Brown	Lighting feed / main lights
Purple	Side light / lighting circuit
Black	Rear light or earth, depending on loom
Pink	Brake / stop light
Yellow	Lighting feed from stator
Blue	Headlamp circuit
Red	Headlamp circuit
White	Horn circuit
Earth	May vary depending on loom/component

The important thing is to use this table as a starting point, not as a substitute for the correct wiring diagram.

Why Replacement Wiring Looms Can Be Different

If you've bought a new wiring loom for your Lambretta, don't be surprised if some wires don't appear to match the original loom.

Modern replacement looms may be designed around:

Electronic ignition
Modern regulators
Battery systems
Non-battery systems
Different ignition switches
Different light switches

Some manufacturers also change the wiring arrangement to make the loom easier to install with modern electrical components.

This is why you should always identify which loom you have before connecting it.

Our Biggest Tip – Don't Guess!

If you're unsure about a Lambretta wire, don't just plug it into the nearest available terminal because the colour looks right.

Take a few minutes to identify:

Which model Lambretta you have
Whether it is battery or non-battery
Which loom is fitted
Which ignition system is fitted
Which regulator is fitted
Which ignition switch is fitted
Which light switch is fitted

Then follow the correct wiring diagram.

A few minutes spent checking can save hours of chasing electrical faults later.

Wiring a Lambretta During a Restoration

If you're completely rebuilding a Lambretta, we recommend installing the wiring loom and cable outers before the engine, legshields and other components make access difficult.

This is something we covered in our guide on how to assemble a Lambretta LI, SX or TV Series 3.

Planning the wiring at the beginning of a restoration makes the final assembly much easier.

Need Lambretta Electrical Parts?

At Scooter Vista, we stock a wide range of Lambretta electrical and restoration parts for LI, SX, TV, DL and GP models.

These include:

If you're unsure which electrical parts you need for your Lambretta, get in touch and we'll do our best to help you identify the correct components.

Final Thoughts

Lambretta wiring can look complicated, but once you understand what the different wires are generally used for, it becomes much easier to follow.

The most important thing to remember is that wire colours are a guide, not a guarantee.

A 50-year-old Lambretta may have had several owners, repairs and modifications during its life, so always check the wiring against the correct diagram for your particular scooter.

Take your time, check your connections, make sure your earths are clean and never be afraid to use a multimeter to trace a circuit.

Once you've got the wiring right, the rest of the electrical system becomes much easier to understand.

Here's a video from Rob at kickback garage that may help you

Scooter Vista – keeping classic Lambrettas on the road.

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