Low Beam Lights Acting Weird

[Steveman]

My dads truck recently just developed a problem where his low beam lamps will intermittently not work. Unfortunately I do not live with him so I cannot see the problem but he says that one day they both stopped working at the same time. He has replaced the bulbs, checked the fuses, and checked a relay switch (I do not know which one), all to no avail. Then tonight he was talking to me on the phone and they suddenly started working. Anybody know what could be going on? I was thinking that maybe the light sensor that senses if its day time or night time might be acting up. Lastly every other light on the truck works fine.

[brims]

Do the dash lights change when the headlights turn on and off on their own? As in going to low light mode for night driving. If so then that would point to the light sensor, if not, hopefully someone else will have some ideas.

[ColeTrains03]

when my light sensor went bad on my '00 Silverado my DRL's didn't work and always just triggered my headlights. After i replaced it my DRL's and headlights worked as should