Did you apply the parking brake first?
Color me stupid, I did not realize that when you put the vehicle in park, the DRL's turn off. My previous vehicle (2002 Jetta) only turned off the DRL's when the parking break was activated. So there's no way to verify it worked unless you're able to put the car in gear to see if they're on. Took me a few days to notice the DRL's were on as I was driving behind others. I tried several times, with the parking break on, to get it to work, but am still unable to.