No lights on an electric vehicle: blown bulbs, brake light and number plate light

A lighting failure is most often caused by a blown bulb or by a problem in the 12 V circuit: a damp or corroded connector, a loose wire, a fuse or the voltage converter. If only one function fails (for example the brake light or the number plate light), start with the bulb and the visible connectors. If everything fails at once, the cause is usually in the power supply to the whole lighting system.

This advice is based on solutions to specific, anonymised cases handled by Amperi Service. Every case can be different – the steps described do not replace a professional service diagnosis.

Symptoms

The front or rear light does not work.
The brake light does not come on when braking.
The number plate light does not work.
The indicators do not work and the indicator relay does not click.
All lights fail at the same time.
The lights work intermittently, for example after bumps or rain.
The position lights do not work although the other lights do.

Possible causes

A blown bulb (front, rear, position, brake or number plate light).
A damp or corroded connector from which the power wire falls out, for example the indicator relay connector.
Damp connectors at the ignition switch, which cut the power supply to the lighting.
A damaged fuse holder or a blown fuse in the lighting circuit.
A damaged power plug for the lights.
A damaged Anderson-type plug at the controller.
A failure of the voltage converter that steps the high voltage down to 12 V and powers all the lighting.
Several worn bulbs failing at the same time, for example the position lights, which are best replaced together.

What you can check

Switch the vehicle off, remove the key and let everything cool down. Do not open the battery or any high-voltage electronics.
Establish the scope of the fault: check the position lights, dipped beam, indicators, brake light and number plate light one by one. If one function fails, the cause is usually the bulb or its connector. If all the lights fail, suspect the 12 V supply.
Check whether other 12 V items work, such as the horn, warning lights or display. If they do not, the problem is in the 12 V supply rather than in a single bulb.
Inspect the faulty bulb. A broken filament or a dark deposit inside the glass means the bulb has blown.
Replace a blown bulb with an identical one of the same type and rating as in the housing or in the vehicle manual. Do not touch a halogen bulb with bare fingers (hold it by the base, or use a clean cloth or glove), because skin oil shortens its life. Keep the housing dry and clean.
With the vehicle switched off, visually check the easily accessible connectors near the light units. Look for moisture, green or white deposits and loose wires. Gently press a loose connector back into place.
If the vehicle manual identifies an accessible fuse for the lighting circuit, check it. Replace a blown fuse with an identical one of the same rating. Never fit a higher-rated fuse. If the fuse blows again, there is a short circuit in the circuit that needs diagnosis.
Switch the ignition on and test all the lights again, including the brake light (with the brake lever applied) and the number plate light.
Do not ride on public roads without working lights, especially after dark. A working brake light and indicators are needed in daylight too.
To prevent the problem, avoid pressure-washing around the ignition switch, connectors and light units. Check all the lights regularly. If several bulbs are clearly worn, consider replacing the whole set.

Follow safety rules when working with batteries and electrical equipment. Do not open batteries or high-voltage electronics. Unauthorised modifications to the equipment during the warranty period may void the warranty.

When to contact the service

Professional repair is needed when all the lights fail at once, the indicators do not work despite good bulbs, a fuse blows again, there is visible corrosion or melted connectors, there is a smell of burning, or replacing the bulb does not restore the light. The same applies if a fault in the 12 V converter, the Anderson plug at the controller or the connectors at the ignition switch is suspected. Diagnosing these parts requires measurements and work on the vehicle's electronics, so it should not be done by the owner.

FAQ

Why is none of the lights working even though the bulbs look fine?

Most often the 12 V supply is missing. The cause may be a fuse or its holder, a damaged power plug for the lights, the connectors at the ignition switch, the Anderson plug at the controller or the 12 V voltage converter. A workshop should check these parts.

The indicators do not work but the bulbs are good. What could be the cause?

A typical cause is a missing power supply at the indicator sockets or at the indicator relay (flasher unit). It is often a corroded connector from which the power wire has fallen out, or damp connectors at the ignition switch. The relay or the switch itself may also be faulty.

What should I check if the brake light does not work?

Start with the rear bulb or rear light unit and its connector. Check whether the other rear lights work. If the rest of the lighting is also out, look for a problem in the 12 V supply.

Why is the number plate light not working?

First check the bulb or light source and its connector for moisture and loose contact. If the other rear lights are also out, the cause may be a shared supply, such as a fuse or a connector.

Can I replace a bulb myself?

Yes, if the housing is easy to reach and the vehicle is switched off with the key removed. Use a bulb identical to the original. If it is a halogen bulb, do not touch the glass with bare fingers. Do not open the battery or any high-voltage electronics.

The fuse blows again after replacement. Can I fit a higher-rated one?

No. Repeated blowing means a short circuit or overload in the circuit. A higher-rated fuse can damage the wiring or cause a fire. The circuit needs to be diagnosed in a workshop.

Problem still there? Open a service request with Amperi Service – we will help.

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Updated: 2026-10-31 · Serwis Amperi · serwis@amperi.eu