Hi Guys!!
I've just self-solved my problem!
Yes, it's an after-market unit, made to replace the OEM with plug-n-play change. All wires and harnes were included for that, so the car module still "thinks" that the OEM halogen unit is there...
My U didn't stay on as it was assigned as a DRL (replacing the OEM halogen DRL, which turns off when head-light is on).
What I did with VCDS was search for the DRL output light, and assigned a second function to it for normal low beam. This means that the same light now works either as a DRL and as a Low Beam:
My car is a Golf MK7 (MQB) - 1.4 TSi (Germany made - Brazil Market Higline):
[09] Cent. Eletronics
Code 31347
Adaptation
(5) – Leuchte4TFL LB4 – Lichtfunktion B 4 (Whitch is a B function for the LEFT DRL output)
Default: NOT ACTIVE
Changed to: Abblendlicht Link (Left Low Beam)
&
(5) – Leuchte5 TFL RB32 – Lichtfunktion B 5 (now for the right side)
Default: NOT ACTIVE
Changed to: Abblendlicht Rechts (right low beam)