Tonight both low beams went out. Had to use the fog lamps to get home. The hi beams work, but no lo beams. The is a small lamp looks to be like next to the hi beam bulb that was on. I guess that is the DRL. Anyway it seems unlikely that both bulbs would go out at the same time. What would be the best way to trouble shoot this problem? Is there a separate fuse for the lo beams? Maybe a switch problem? Any ideas really appreciated.

 

The small lamp is the parking lights (looks like a #194 bulb). There is a fuse for the low beams. I'd start with the easiest and check the actual bulbs first. I'm going to assume you have regular halogen headlights and not Xenon? Usually one light was already out and the driver didn't notice until the other goes out. If it was a switch problem, the fail safe is for the lights to be on all the time (key on). There are many things that could cause this, multifunction switch, relay, even the ignition switch BUT most likely other things would quit working at the same time with an ignition switch fault. As I said, start by checking the bulbs and go from there.
Sorry, don't know off the top of my head which fuse (or fuses) serves the headlamps.

 

Had to check for my own curiosity. Headlamp fuse is S19 (fuse 19 in the left side fuse panel), 15 amp. The headlamp switch "tells" J519 vehicle electrical control module to energize the relay (inside J519) to turn on the headlamps. JJ519 module could be the cause but is highly unlikely (rare they ever fail). Hope this helps more than hinders!