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Installing Extra Lights: The Complete Step-by-Step Guide

October 14, 2025

Installing extra lights on your car is one of the most rewarding upgrades you can make. The feeling when you turn on the high beams and a wall of light turns night into day is unbeatable. For many, the installation feels like an overwhelming project, filled with technical jargon and a fear of damaging the car's sensitive electrical system.

It doesn't have to be that way.

We at Xenonkungen have helped thousands of customers with their installations since 2004. We have seen all the problems, answered all the questions and know exactly where the common pitfalls are. That is why we have created this guide. Don't think of this as an instruction manual but a complete walkthrough based on real experience, designed to confidently guide you through each step, regardless of whether you have an older car or a brand new one with an advanced CANBUS system.

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Before You Begin: Preparation is Key

A successful assembly starts with the right preparation. Having all the parts and tools ready before you start makes the whole process smoother and more enjoyable.

Always start by disconnecting the negative terminal of the car battery. This prevents short circuits and protects both you and the car's electronics.

The tools you will need:

  • Screwdriver set
  • Block wrench set or socket wrench set
  • Drill and drill bits (to attach the holder)
  • Cable lug pliers / Stripping pliers
  • Multimeter (highly recommended for older cars)
  • Cable ties to secure cables neatly

 

The parts required for a professional installation:

  • Extra lights: Of course.
  • Additional light holder: A stable, model-specific or universal holder is the basis for a vibration-free light image.
  • Relay wiring kit: The heart of the installation. This ready-made wiring kit includes a relay, fuse, switch and protected cables. It ensures that the auxiliary lights are powered directly from the battery, which is safer and more efficient. Never use a homemade solution.
  • CANbus interface (for modern cars): If your car is from around 2005 or newer, an interface like the XBB Dongle is the strongest recommendation. More on this below.
  • Stabilizing struts: Highly recommended, especially for larger auxiliary lights, to prevent vibrations.

 

See our ready-made Luxtar Stellar kit with everything you need for installation: https://xenonkungen.com/produkt/luxtar-stellar-black-rad3-canbus/ 

 

Step-by-Step: From Cardboard to Fully Assembled

Follow these steps carefully for a safe and professional installation.

 

Step 1: Install the Auxiliary Light Holder and Auxiliary Lights

Start with the physical installation. The auxiliary light holder is usually mounted behind the license plate.

  • Unscrew the license plate.
  • Position the auxiliary light holder and mark where you need to drill. Be careful not to drill into the crash beam unless necessary.
  • Drill the holes and attach the holder securely. Use stainless steel screws.
  • Mount the auxiliary lights on the bracket, but do not tighten them completely yet. We will make the final adjustment at the end. Also mount the stabilizing struts if you have them.

 

Step 2: Pull the Relay Cable Kit

Now it's time for the electricity. Think of a logical and protected route for the cables.

  • Place the relay near the battery in a dry place.
  • Connect the red (+) and black (-) cable lugs directly to the battery terminals.
  • Run the cables with DT connectors (the ones for the lights) to the auxiliary lights. Use cable ties to secure the wiring neatly and prevent it from rubbing against sharp edges.

 

Step 3: Finding and Connecting the Control Current – The Critical Step

The control current is the small signal that tells the relay to turn on the auxiliary lights when you turn on your regular high beams. This is where most people make mistakes. The method is completely different between older and newer cars.

Method A: Traditional Wiring (For cars without CANbus, usually before 2005)

On an older car, there is a physical positive cable (+12V) to the high beam bulb from which we can "steal" the signal.

  • Find the wiring harness that goes to the car's headlights.
  • Use a multimeter to identify which wire provides +12V only when the high beams are on. This is your signal wire.
  • Connect the relay cable set's signal cable (usually blue or white) to this cable using a cable lug or, for best results, by soldering and insulating with heat shrink tubing.


Method B:
Modern Wiring (For cars with CANbus, LED or Xenon)

On a new car, the lights are controlled digitally via the car's computer (CANBUS). Trying to "steal" power here can lead to error codes, flickering lights or, in the worst case, damaged components. You should not use a multimeter to look for the signal here. The solution is a CANbus interface such as the XBB Dongle.

  • Plug the XBB Dongle into the car's OBD-II socket (usually located under the steering wheel).
  • Download the associated app to your phone and select your car model.
  • The dongle now reads the car's CANbus data wirelessly and sends a signal to a small receiver (PowerUnit) to which you connect the relay cable set's signal cable.


Results:
A 100% safe, interference-free and incredibly smooth connection without any damage to the car's original cables.

See XBB Dongle and Powerunit: https://xenonkungen.com/produkt/xbb-obd-ii-dongel-powerunit/ 

 

Step 5: Final Connection, Testing and Adjustment

  • Connect the DT connectors from the relay wiring harness to the auxiliary lights.
  • Double check all connections.
  • Reconnect the negative terminal to the battery.
  • Start the car and test! Turn on the high beams and see if the auxiliary lights come on. Also test your manual switch if you have one installed.

 

Once everything is working, park the car on a flat surface in front of a wall (about 10 meters away) and adjust the direction of the auxiliary lights. A good rule of thumb is that the center of the beam should be just below the height of your regular high beam to avoid glare at the top of the hill. Tighten all screws when you have the desired position and secure the last loose wires with cable ties.

 

Voila! Now you have your new Extra Lights mounted and ready.

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Team Xenonkungen