Auxiliary driving lights boost visibility on dark roads, yet poor installation can cause glare and legal trouble. This guide explains the regulations, technical requirements and everyday use so you combine maximum light output with full compliance.
What counts as an auxiliary light?
Auxiliary lights are fitted in addition to the car’s original high beam to increase forward illumination. Typical setups are LED light bars, round spotlights or combinations of spot and flood patterns. They must always be wired so they only operate together with the main high beam.
See the overview in Lights and light types and how to use them in Driving in the dark.
Regulations and approval
| Area | Requirement | Practical tip |
|---|---|---|
| Approval | Lights must be E- or CE-marked and approved for road use | Buy from reputable suppliers; random imports may lack approval |
| Quantity | No upper limit, but lights must not dazzle other road users | Combine narrow spot beams with wide flood beams for balance |
| Activation | Auxiliary lights must dim automatically with dipped beam | Use a relay or CAN interface to avoid dashboard errors |
| Placement | Mount symmetrically without extending beyond vehicle width | Measure carefully and review the Vehicle regulations |
| Height | Aim for 25–120 cm above ground for best effect | Lower mounting reduces glare for oncoming traffic |
Mounting and positioning
- Choose brackets that handle vibration and harsh weather; stainless or powder coated steel lasts longest.
- Integrate the switch with the original system so you do not disturb the vehicle safety equipment.
- Seal cable entries with rubber grommets and follow Car maintenance guidelines to prevent corrosion.
- Retighten bolts after the first 200 km to prevent vibration damage.
Placement guide
| Vehicle type | Recommended placement | Comment |
|---|---|---|
| Passenger car | Lower grille section | Keeps cooling airflow and limits glare |
| SUV/motorhome | Above licence plate or roof edge | Add shielding to avoid bonnet reflections |
| EV with active grille | Number plate bracket or dedicated mount | Protects airflow to battery cooling |
Electrical connection
- Locate the high-beam trigger (often in the right headlamp module) and use a tap or adapter.
- Install a relay with its own fuse close to the battery; see Electronic stability control for details on sensitive electronics.
- Route cables with sufficient cross-section (minimum 2.5 mm² for powerful LED bars) and protect them with conduit.
- Test the setup: auxiliary lights must switch on and off with the high beam and not cause dashboard warnings.
Using the lights in practice
| Situation | Best practice | Reference |
|---|---|---|
| Oncoming traffic | Dip to low beam in good time to avoid glare | Using lights and signals |
| Rural driving | Plan dimming at crests and bends, combine with scanning techniques | Positioning and driving style |
| Parked vehicle | Switch off auxiliary lights to avoid heat and battery drain | Climate control and cabin air |
Inspection and maintenance
- Clean lenses regularly and polish when needed to maintain output.
- Check cable joints at every EU inspection.
- Align the beam together with the main headlights to keep a level cut-off.
- Carry spare fuses and tools in the car, see Mandatory safety equipment.
Common mistakes and reactions
| Mistake | Consequence | Solution |
|---|---|---|
| Missing approval | Noted at inspection, possible fine | Document E-marking before presenting the car |
| Auxiliary lights stay on with dipped beam | May lead to fines or penalty points | Wire through a relay or reprogram the control unit |
| Sharp edges or protrusions | Can trigger remarks at technical inspection | Use approved brackets with protective edging |
Pre-drive checklist
- Confirm that the auxiliary lights are clean and undamaged.
- Test that they dim together with the low beam.
- Secure all cables and connectors against moisture.
- Re-adjust the beam after adding roof load or a trailer.
Frequently asked questions
Are coloured auxiliary lights legal?
No. Only white light may face forward, see the Vehicle regulations.
May I use auxiliary lights with automatic high beam?
Yes, provided the systems integrate properly. Learn more about automation in Automatic high beam.
Do I need to inform my insurer about auxiliary lights?
Normally not, but high-value light bars can be listed as equipment in Insurance and coverage.