The DRL is on the Bi-xenon headlamps on pre facelift A3. yes good point on the headlight switch but i was wondering how it is as standard for those with S3's or A3s that had the bi-xenon from factory with Auto lights. as my Auto-lights retrofit is almost complete i am wondering how it should work once its all done. i am thinking it should work as when the headlight switch is set to off then no lights at all, when set to auto in daylight the DRL comes on and in night time the headlights come on. however currently when the light switch is set to off the DRL is on.