My girlfriend has a 2006 Pontiac g6 gtp. This weekend I noticed that at some point her headlights weren't working. My first thought was that I had turned off the automatic running lights by accident. Once I verified that the auto lights were on, but we still had no headlights, I tried to manually turn on the headlights. Once again, I found that we had no lights. We were driving at night at the time so I had to ride home with the high beam lights on. The high beam lights work fine, as do the side marker lights, but no low beam. I'm wondering if anyone else has had this happen and where should I be looking to troubleshoot the problem. Thanks in advance.