I have the same one on my 08 ultra and it works great. I feel safer with it and don't care what the anti headlight modulator people think. I have one for the taillights too!!! But in regards to your problem with it not working, sounds like the daylight sensor is maybe losing connection or has broken wire or modulator is bad ( was it overloaded?) At night, mine will flash 8 times till it realizes it is night and then stays on high beam (no flash) thats what makes me think it is something with light sensor. Hope this helps.
I discovered that I can buy just the sensor and replace it, so I think I'll do that. The whole thing is $100+--and I can buy the sensor for $10 or so.