So my 2017 has been doing the same thing. I showed dealership a video of it and he told me it’s because the OnStar antenna seal is loose so moisture probably got inside and corroded connections. Said $900 to replace the antenna. That makes no sense to me and it’s loose I guess you could say but you have to wiggle it pretty hard to get it to move around.
so has anyone actually had this issue fixed and what did it end up being? I don’t plan on keeping truck more than 2 more years so I’m not gonna do anything super expo to fix. It’s a mild inconvenience.