This article clarifies how to adjust Daytime Running Light (DRL) brightness on a MK7 Volkswagen Golf R with factory LED headlights using VCDS. A common misconception is that increasing “Dimmwert CD” values will brighten DRLs. This guide explains the correct procedure.
Decoding DRL and Parking Light Functionality
It’s crucial to distinguish between Daytime Running Lights (DRLs) and Parking Lights (PLs). DRLs operate when low-beam headlights are OFF, while PLs function when low-beams are ON. On a UK-spec MK7 Golf R with LEDs, VLB10 and VRB21 control the left and right front lights respectively.
Lichtfunktion A (Daytime Running Lights):
- Controlled by Dimmwert AB, which dictates DRL brightness.
- The factory default for Dimmwert AB is typically 100, representing maximum illumination.
Lichtfunktion C (Parking Lights):
- Controlled by Dimmwert CD, which dictates PL brightness.
- Adjusting Dimmwert CD only affects parking light brightness and has no impact on DRLs.
- Lichtfunktion D controls single-side parking light functionality.
Understanding Dimmwert and Lasttyp
While you might encounter Dimmwert values up to 127 for LEDs, this applies to specific Lasttyp (Load Type) settings using digital control. The factory LED DRL setup on the MK7 Golf R likely uses “analogue control” for Pulse Width Modulation (PWM) with a maximum Dimmwert of 100. Both 100 in the analogue setting and 127 in a digital setting achieve maximum brightness for their respective control methods. Therefore, simply increasing Dimmwert values beyond the intended maximum for your Lasttyp will not result in brighter lights.
Adjusting DRL Brightness with VCDS
Because the factory setting of Dimmwert AB (100) already represents maximum DRL brightness, increasing it further will have no effect. To reduce DRL brightness, lower the Dimmwert AB value within VCDS. Conversely, to adjust parking light brightness, modify Dimmwert CD.
Conclusion
Adjusting DRL brightness on a MK7 Golf R with factory LEDs requires modifying the Dimmwert AB value within Lichtfunktion A using VCDS. The factory default of 100 represents maximum brightness. Lowering this value will dim the DRLs. Adjusting Dimmwert CD only impacts parking light brightness when the low beams are on. Understanding the difference between these settings is crucial for proper DRL adjustment. Remember to always proceed cautiously when modifying vehicle settings with VCDS. Incorrect adjustments could potentially lead to unexpected behavior or fault codes.
