Truck is stock except for new headlights nothing fancy, just simple replacements. Had an issue with the truck not starting before they were changed. Everything would power up but trucj justed clicked. Boosted then was fine for a couple months. Recently i had a tailight lense crack no big issue then i got a brake light out message? But lighyt still works fine. Had multiple starting issue since, voltage guage fluctuating a little with signals and drastically when going to highbeam. Changed the battery and still does it. Any suggestions as to the problem?