2013 Tahoe LTZ 5.3 with 132k miles, I just purchased this rig in December of 2022.
A couple weeks ago I was getting in my truck to go home from work at 11:30pm so it was dark, for the first 10 minutes of my drive I noticed all of my lights going dim and normal and would repeat this about every 5-10 seconds and stopped out of the blue as if it needed to warm up first . Nothing could replicate it while voltage meter on dash showed stable and no performance issues at all!
A couple weeks goes by until today same thing happened, I got home checked all my grounds, they were all shiny and snug and I checked the positive cable on the battery also. This only happened twice now in the 8k miles since I’ve owned this vehicle. Alternator appears original
I will say I do notice sometimes the headlights and interior lights flicker very little if I’m paying attention while idiling . This happened out of the blue and while this is happening the volt meter doesn’t even flinch and stays steady above 14v. Battery is interstate made in 2019 by the way. Any insights are appreciated
One thing to be aware of, MANY people make modifications (in software, or hardware) in order to disable the Daytime Running Lights, or otherwise have full control of the lights. (Don't do this in Canada, they're required there.) In newer, GM vehicles, the Daytime Running Lights, are dedicated, so problems with the main headlights should not occur. However, in older GM products they would dim the main headlights to serve as the DRLs. This made disabling the DRLs more complicated. Most GM vehicles sold to government agencies, have the Daytime Running Lights disabled. They do this through software, not hardware modifications. I am not saying this is your problem, but do consider it as a possibility. On current GM vehicles, the Daytime Running Lights can be completely disabled on every engine start. So technically, General Motors Can no longer be accused of having "Forced Lighting".