So I received my car back from its 12,500 annual service today. I had scheduled the LTE upgrade to take place at the same time. It turns out I also had some major issues, discussed elsewhere, involving bad wiring done by an aftermarket installer, the result of which was that my main wiring harness had to be replaced. (I mention that in case the GPS issue could be related to that, and not to the LTE upgrade.) The first thing I noticed that was odd was that my air suspension didn't adjust at my driveway. I didn't think much of it, and figured the setting had been cleared. I adjusted the suspension manually, thinking it would create a new setting. Later, I noticed the same issue. Looking more closely, I realized my Homelink setting for the garage door also was not presenting. And when I manually selected the Homelink screen, the setting for the garage door was not green. I realized at that point I had a GPS issue. To confirm, I started the nav system, and that indicated I was still at the service center. I tried the scroll wheel reset, as well as the other one (the IC reset, using the buttons above the scroll wheels), and neither helped. By this time I needed to get to an appointment and did not have time to call the service center at that time, and also thought that perhaps leaving the car outside and parked for some time might help, even though it had been outside for the four-plus hour trip from the service center to me, while on the trailer. When I still had no GPS connectivity over an hour later, I did call the service center. They said they would try to look into it remotely, and called me back a couple of hours later, just a little while ago, to say that someone would call me tomorrow. My best, uneducated guess, is that somehow some GPS antenna or something did not get hooked back up properly. Does this sound plausible? Would the GPS antenna be disconnected during the LTE upgrade? Thanks in advance for any light anyone here may be able to shed on this for me while I wait until tomorrow to hear back from my service center.