2016 Yukon XL SLT, GPS not working. My wife and I noticed this about a month ago while traveling out of town. I was at the dealership earlier today for something unrelated and asked the service advisor and he said it most likely is the shark fin antenna and said it would be almost $400 to replace. I read up on the antenna issue and from what I understand the satellite radio uses that antenna as well, but it works just fine. Then it dawned on me, we had the windshield replaced back in March. I don't replace windshields so I don't know if they would have been anywhere near the wiring for the antenna or not. Curious if anyone else has had the same problem. Thank you in advance.