Activation of standard daytime running lights (DRL) on most modern cars is done through the on-board computer menu or a diagnostic scanner if the option was disabled at the factory. Owners of cars without factory functionality have to implement a separate relay or connect the headlights directly to the ignition circuit to ensure that the lights automatically turn on when the engine starts.
Depending on the brand of the vehicle, the algorithm of actions is radically different: some systems require entering a hidden engineering menu, others require a physical jumper of contacts in the fuse box. Software activation often accessible via the multimedia screen, while older models may require intervention in the electrical circuit VAG or BMW.
Software activation via on-board computer
Modern cars allow you to control external lighting without the use of additional equipment. To do this, you need to find the corresponding item in the vehicle settings menu. Typically the path looks like Vehicle settings — Lighting — DRL. If the slider is inactive, turning it on will immediately start the lamps.
In some models, for example Hyundai or Kia, activation may require sequential pressing of buttons on the dashboard. The owner must hold the key OK on the steering wheel or control lever for a few seconds with the ignition on. The screen will flash to confirm that you have entered setup mode, and you can then select the desired option.
It is important to consider that on-board computer can block DRL activation if the light sensor detects darkness. In such cases, the system will turn on the low beam with priority, ignoring the settings of the running lights, which is the standard behavior of the electronics.
Hidden menus in different car brands
To enter the hidden menu on Audi/VW you often need to hold down the “Car” or “Setup” button, and on Ford you need to press a combination of buttons on the radio.
Using diagnostic equipment for setup
If the menu does not provide the necessary options, you will need to connect a specialized scanner. For group cars VAG (Volkswagen, Audi, Skoda) program used VCDS or VAG-COM. The connection is made via the OBD-II connector, after which you need to go to the central electrical equipment control unit.
In the coding section 09-Cent. Elect. you need to find the byte responsible for DRL and change its value. Often it is byte number 3 or 4 where the bit needs to be changed from 0 to 1. After applying the settings (Do It!) and reboot the unit, the running lights will work automatically.
For French cars Renault and Peugeot utility is applied PyRen or Ddt4All. Here the process looks more complicated: you need to find the parameter Daytime running lights in the BCM (Body Control Module) configuration and activate it. Changing configuration files without a backup copy may result in electrical equipment malfunctions.
To successfully activate through a scanner, be sure to save the original coding sheet (Long Code Helper) so that you can roll back the changes.
Connection diagrams via relay and control unit
When software methods are not available, the only solution is a physical connection. The most reliable way is to install five-pin relay. It allows you to separate the power circuits and control the inclusion of DRL only when the engine is running, preventing the battery from being discharged while parked.
The connection diagram requires precision: pin 30 is connected to the battery positive through a fuse, pin 87 is connected to the running lights themselves. The control signal is supplied to pin 86 from a circuit where voltage appears only after the engine starts (for example, from an oil pressure sensor or generator).
- 🔌 Contact 85 is connected to vehicle ground to complete the control circuit.
- ⚡ Contact 87a (if used for opening) is isolated, since it is not used in the standard switching circuit.
- 🛡️ Be sure to use a 10-15 Amp fuse at the relay power input.
An alternative is ready-made DRL control unit, which independently monitors the voltage in the on-board network. When the voltage rises above 13.5 Volts (engine start), the unit supplies power to the lights, and when it decreases, it turns them off.
Features of connection in cars of different brands
Each manufacturer has its own technical features for the implementation of lighting devices. In cars Lada Vesta or Granta Often the wiring is already installed, but the lamps themselves are not installed or the software in the ECU is not activated. In such cases, it is enough to replace the plugs in the headlights with LED modules and register the configuration via ELM327.
In Japanese cars such as Toyota and Mazda, a common practice is when DRLs are implemented through the bright glow of side lights or fog lights. To fully activate them, it may be necessary to resolder resistors in the headlight unit or install additional relays to separate operating modes.
German automakers strictly regulate the operation of lighting equipment. B BMW Series 3 or 5, DRL activation is often tied to the generator load sensor. Trying to simply connect to the positive may cause an error on the dashboard indicating that the lamps are faulty due to the low resistance of the LEDs.
Diagnostics of malfunctions of running lights
If the lights stop lighting or do not work correctly, it is necessary to carry out diagnostics. The first step is always to visually inspect the lamps or LED strips for burnout. Modern headlights often use a series connection of diodes, so the output of one element can extinguish the entire circuit.
Next, the integrity of the fuses is checked. The owner's manual will usually indicate the fuse designation DRL (often labeled as Day or Light). If the fuse is intact, use a multimeter to check the presence of voltage at the headlight connector when the ignition is on.
| Symptom | Probable Cause | Test method |
|---|---|---|
| Lights don't turn on | Fuse blown | Continuity tester |
| Flickering during operation | Poor ground contact | Visual inspection of terminals |
| Burn dimly | LED degradation | Replacing the DRL module |
| Panel error | Resistance mismatch | Diagnostics with a scanner |
A common problem with LED DRLs is the lack of CAN buses or incorrect impedance load. If you have installed non-standard lamps, the system may perceive them as faulty and turn off the current supply.
Legal Considerations and Installation Requirements
The installation of daytime running lights must comply with technical regulations. According to the rules, DRLs should turn on automatically when the engine starts and turn off when the low beam is turned on. Using fog lights as DRLs without proper markings and settings may result in a denial of entry. technical inspection.
The brightness and color of the glow are also regulated. Only white light spectrum is allowed. The installation of blue, red or yellow “running lights” is prohibited and entails penalties, as this misleads other road users.
⚠️ Attention: Tapping into the wiring yourself without installing fuses can lead to a short circuit and fire of the car. Carry out all work with the battery terminal disconnected.
If the vehicle was not originally equipped with DRL, the legislation of many countries allows the installation of certified additional modules. The main condition is their correct location on the body (at a height of 250 to 1500 mm from the ground) and symmetrical installation.
☑️ Check before departure
Tips for choosing and replacing DRL lamps
When replacing burnt-out elements or upgrading lights, it is important to choose high-quality components. Cheap Chinese analogues often do not have thermal stabilization, which leads to rapid burnout of crystals and changes in color temperature. It is recommended to look for brands with a guarantee, such as Osram or Philips.
For cars with a lamp monitoring system (Check Control), it is necessary to select LEDs with built-in trickles (CAN-bus). These are resistors that simulate the resistance of a regular lamp filament, preventing errors from appearing on the dashboard.
- 💡 Pay attention to the glow temperature: optimally 5000-6000K.
- 🌧️ Check IP67 or higher for moisture resistance.
- 🔍 Make sure the base is compatible with your car model.
Do not forget that even when replacing one lamp, it is better to replace them in pairs. New LEDs may shine brighter or have a different shade compared to expired ones, which will create lighting asymmetry.
Wipe down the running light bulbs every time you wash them. Pollution significantly reduces their visibility and effectiveness, especially in cloudy weather.
Can fog lights be used as running lights?
Technically this is possible, but legally only permissible if the fog lights are marked accordingly and turn on automatically with the engine, going out when the low beam is turned on. In most cases, this requires complex modification of the circuit.
Why do the DRL light up at full intensity after turning on the low beam?
This is a standard feature on many cars. The running lights do not turn off completely, but reduce their brightness, working in the side lights mode, so as not to dazzle oncoming drivers and save the life of the LEDs.
How can I check if DRL is activated in my car?
Start the engine and turn off all other lights. If the front lights are white (not the yellow/orange lights), then the DRLs are active. You can also check the status in the on-board computer menu.