I have had the same problem " BUT one 2 weeks apart both Low beam headlamps have blown out 2007 Chevy Silverado 2500HD.
I have changed the bulbs 2x's the worked for a while and then would go out. So I replaced both "Pigtails" on both sides as I noticed one of the wires was burnt.
That seem to work for about a month and now the pass side low beam is out again.
I inspected the bulb inside the pass side and it is good. Must be something else . I read some said they had other issues and they replaced a FCM?
Not sure what that is.
Or is there another part I need to check? Any help. This is so weird.