Wiring High-Beam Lights
If you want to connect an approved high-beam light or high-beam light bar, the easiest method is to link it to the vehicle's existing high-beam system. Typically, you use the power that activates your standard high beams to trigger a relay, which in turn switches on the auxiliary high-beam light. Typically, you use the power that activates your standard high beams to trigger a relay, which in turn switches on the auxiliary high-beam light. Typischerweise nutzt man den Strom, der das normale Fernlicht aktiviert, um ein Relais auszulösen, das wiederum das Zusatzfernlicht einschaltet. Normally, the current that powers your regular vehicle high beams switches a relay that then activates the auxiliary high beams. Normalerweise schaltet der Strom, der das normale Fernlicht Ihres Fahrzeugs versorgt, ein Relais, das dann das Zusatzfernlicht aktiviert. Here is a simple wiring diagram for this setup:
1) Simple connection for auxiliary high-beam lights
With this setup, the auxiliary high-beam light always turns on and off in sync with the vehicle's high beams. This is not recommended if the high-beam light is mounted above the windshield, as using it can cause glare reflecting off the windshield, hood, dust, or rain. In such cases, we recommend a setup where the auxiliary high-beam light can be switched on selectively.
This wiring setup can be implemented using the following items from our shop:
- Wiring harness SL-ST-270477 or SL-ST-270477-24 (24 V) – for connecting a high-beam light via a 2-pin DEUTSCH DT connector.
The connector can be changed to a higher-power DEUTSCH DTP connector.
- Adapter cable 1-to-2 DEUTSCH DT SL-ST-270442 – You need this adapter when connecting two auxiliary high-beam lights.
- Adapter cable SL-ST-270438 – If you want to connect auxiliary high-beam lights that feature more than just the standard white high-beam function (and use a 4-pin DEUTSCH DT connector), you need one of these adapters for a pair of lights. The second adapter is included with SL-ST-270477.
- Adapter cable SL-SL-AK-H42R-AMP or SL-SL-AK-H72R-AMP for H4 or H7 high-beam bulbs, used to tap the switching signal for the auxiliary high-beam light.
2) Connecting the auxiliary high-beam light with an additional switch
If you want to switch on the auxiliary high-beam light independently of the vehicle's standard high-beam, you need an additional switch. You switch on the vehicle's high-beam, but the auxiliary high-beam remains off initially. When you operate the second switch, the auxiliary high-beam also turns on. If you then switch off the vehicle's high-beam, the auxiliary high-beam turns off as well. This wiring configuration complies with legal requirements under UN-ECE R48—the regulation governing vehicle lighting systems.
This wiring setup can be implemented using the following items from our shop. Please note that we only sell the wiring harnesses when purchased together with the lights from our shop.
- Wiring harness SL-ST-270477 or SL-ST-270477-24 (24 V) – for connecting a high-beam light via a 2-pin DEUTSCH DT connector. The connector can be swapped for a higher-power DEUTSCH DTP connector.
- 1-to-2 DEUTSCH DT adapter cable SL-ST-270442 – you need this adapter when connecting two high-beam lights.
- Adapter cable SL-ST-270438 – if you wish to connect high-beam lights that feature additional functions beyond the standard white high beam and use a 4-pin DEUTSCH DT connector, you will need one of these adapters for a setup involving two lights. The second set is included with SL-ST-270477.
- Adapter cable SL-SL-AK-H42R-AMP or SL-SL-AK-H72R-AMP for H4 or H7 high-beam bulbs, serving as a tap for the switching signal for the auxiliary high beam.
- Stainless steel push-button switch, green/red illumination, symbol: headlight
3) Connecting auxiliary high beams with additional light functions
Some auxiliary high-beam lights—such as almost all Strands high-beam lights, as well as the Hella Dynaray or Hella Black Magic Pro models—require an additional connection for the white or yellow position light, in addition to the high-beam connection. Standard wiring harnesses do not account for this. For lights with a DEUTSCH DT connector, the adapter cable SL-ST-270438 is available.
It features a 2-pin DEUTSCH DT connector on one side for the wiring harness and a 4-pin DEUTSCH DT connector on the other side for the light. This allows the white auxiliary high-beam or work light function to be switched. For the two additional functions, white... or yellow, you will then have to install your own wiring first Feedback geben Verwende die Pfeile, um die vollständige Übersetzung anzusehen. Tabulatortaste drücken, um Aktionen anzusehen
Our Universal Wiring Harness
Our most frequently used wiring harness is the STRANDS Siberia Pro for a single auxiliary light (part number SL-ST-270477). We explain exactly how it works and how you can use it.
Wiring harness diagram:
This wiring harness is very easy to connect:
- Red cable ring terminal: Connect to battery positive (+)
- Black cable ring terminal: Connect to battery negative (-)
- Brown cable (loose end): Switching signal – Requires 12V to activate (e.g., from a high-beam adapter or a switch)
- Blue cable (loose end): 12V source when the relay is inactive (no voltage on the brown cable) – Intended for switching the position light when using the XBB dongle for the OBD2 port. If not using the XBB, please insulate and secure this wire properly to prevent contact with the ground.
- 2-pin DEUTSCH DT connector: Connect the auxiliary light here. Pin 1 is positive (+), Pin 2 is ground (-).
The connector can be upgraded to the DEUTSCH DTP system, allowing for higher power output.
STRANDS lights and the Osram FX series can be connected directly. You must always pay attention to the maximum power rating supported by the wiring harness:
- 12 V, DEUTSCH DT: maximum 13 A / 156 watts
- 12 V, DEUTSCH DTP: maximum 25 A / 300 watts
- 12 V, custom-selected connector with appropriate rating: maximum 30 A / 360 watts
When switching to 24-volt operation using relay SL-HE-4RD933332-551, the maximum limits are 20 A and 480 watts. This requires switching to the DEUTSCH DTP connector or another connector with an equivalent power rating.
Cable lengths:
- Light connector to relay: 3,000 mm
- Relay to battery: 800 mm
- Control cable to relay: 2,800 mm
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Switching high beams on modern vehicles
UN-ECE Regulation R48 governs vehicle lighting—specifying what lights are used, how many, where they are placed, and how they are wired. It mandates the following for high beams:
- Installation in pairs
- A maximum of six high-beam lights (or three pairs)
- The sum of the reference numbers for all high-beam lights on the vehicle must not exceed 100.
- High-beam lights may be switched on in pairs or all at once.
- All high-beam lights must switch off simultaneously.
To comply with these requirements, the easiest method is to link the auxiliary high beams to the vehicle's standard high beams. With a direct link, the auxiliary high beams operate in sync with the vehicle's high beams; both switch on and off together.
However, this is not always the best solution—especially if the auxiliary high beams are mounted above the windshield. In such cases, it is often desirable to be able to switch the auxiliary high beams on separately.
You can find more information on this under "Wiring high beams."
For vehicles with standard H4 or H7 bulbs, this is easily achieved using our adapters and wiring harnesses.
With modern vehicles featuring Xenon or LED lighting, this is usually more difficult, as a dedicated high-beam signal is often unavailable.
Depending on the vehicle, you have the following options:
- Find or build an adapter cable – If the signals for low beam, high beam, etc., are routed into the headlight as individual control wires (as is the case with the Chevrolet Silverado and its LED headlights), an adapter can be constructed to tap into the high-beam signal—similar to our H4 and H7 adapters—and use it to trigger the high-beam relay.
To do this, you need the vehicle's electrical manual and a complete connector specification, including the connector type if possible. A specialist workshop can then fabricate such an adapter.
- OBD2 interface – All vehicle manufacturers use the OBD2 interface for more than just diagnosing exhaust emission control systems; it serves as the gateway to all electronic functions. Lighting signals are often available via the OBD2 interface.
When this is the case, the XBB adapter can be used to read this signal and transmit it to an electronic switch (XBB Power Unit); this unit resembles a relay and connects to our universal wiring harness.
- CAN-bus adapter – In our view, this is not the best approach, as the CAN-bus line must be opened to splice in the adapter. Following the instructions, you have to locate the correct spot, cut the very thin wires, properly connect the adapter, and reassemble everything. With new vehicles, this can often jeopardize the warranty, as you are introducing an unknown device into the vehicle's "nervous system." Check the details beforehand!
- CAN-bus sniffer – This is a viable alternative, as you do not need to cut or open the CAN-bus wires. They are placed inside a housing that reads the CAN-bus signals via induction. You typically need the sniffer for this, plus an additional device for the desired function—for example, the high beams. If a CAN bus is involved, this option is preferable.
Which relay is the right one?
If you want to build your own wiring harness, it is important to find the right relay. Three factors are key here:
- Relay function
- Pin assignment
- Maximum power rating
Let's go through all three points.
Relay functions
To connect LED lights, you will need one of two relay types in almost all cases: a simple on/off switch or a changeover switch. For example, our universal wiring harness uses a changeover switch.
On/Off Switch
The on/off switch type does exactly what the name implies: the load circuit connected to the light is open (switched off), and when a switching signal is received in the control circuit, it switches on. When the control signal is removed, the relay switches off again.
Changeover Switch
The changeover switch has two load circuits, one of which is closed (switched on) while the other is open. The load circuit that is closed in the resting state (no control signal) is called "NC" (normally closed), while the other is "NO" (normally open). When the control signal is applied to the control circuit, the relay switches over: NC opens (switches off) and NO closes (switches on). Note that one circuit may be capable of handling a higher power load than the other.
This is the case with our XBB switch. The NC circuit can handle a maximum load of 5 amperes, while the NO circuit can handle 15 amperes.
Pinout
The pinout is standardized. However, there are a few variations, so you need to keep this in mind when building the wiring harness. We recommend always using a relay with a socket, as the contacts are locked in place within the socket. This prevents them from slipping off the pins and causing a short circuit. These sockets usually feature a pin layout compatible with common standardized relay types and pin configurations—such as our universal socket: Wehrle SAE 9-pin. If you use a socket, you will also need locking spade terminals; these feature a small metal tab that prevents the contact from falling out.
