Having searched and read some of the posts on this issue, I've come to no conclusion on how to fix it. Admittedly, tearing the dash panel off was kinda fun, probably mostly because I am no mechanic. But I am still frustrated.

-Headlight switch is turned to the correct setting.
-Fuses all appear good.
-Tail bulbs are good.
-No fouling/shorting apparent on the headlight switch contacts.

What's my next step?

 

Could be the Body Control Module going bad

 

Will a bad BCM definitively throw a code on a scan?

Maybe I can do the auto parts store scan.

 

There is a possibility that it WON'T throw a code, as with all electronics

 

Hello, dude I had the EXACT SAME PROBLEM last week, my rear running lights (at night) and my dash lights (at night) would not work at all, I went thru EVERYTHING YOU DID, I have the huge shop manuals from GM, went thru the entire system and everything pointed to 1 item, every single scenario I did, still 1 point of interest... On the passenger side fuse panel , the 2 Nd fuse from the bottom, , the 15 amp fuse, it read GOOD with a fuse tester, then I went thru them all again with a continuity tester, guess what, BAD FUSE, I pulled it, replaced it and to my astonishment, EVERYTHING TURNED ON ! I swear to you, I checked that fuse 3-4 times with a fuse tester." I was so frapin happy, then ticked off because I have a fuse tester that indicates all fuses are good, even though it was bad. I tested the fuse (the bad one) again with the fusee fester after I REMOVED IT, It still showed GOOD and you could see that it was in fact bad, huge issues avoided there after that... Very relieved Just check...Mjc....