[68Timber]

I'm not that good with the 12v but if it were me I'd put that tailgate courtesy light switch back on just to see if that fixes it. I know that's kinda like 'poke it with a stick and see what happens' idea but since it was recently removed and they're both at the rear end of a Burb, maybe somehow on a common circuit? I'm guessing out loud, but that's what I'd try.