Garmin GPS only works when not plugged in

5 days ago my Nuvi stopped completing. It would get to 80% or even 97% and stay there. 2 days ago I updated to the latest maps. It was still stuck searching on my last location, which is 50 miles away. I took it out in the car, but forgot the cable. It worked normally on its internal battery. Once I connected it to the car this morning, the splash screen was normal, but then it went dim and displayed garmin.com/express. It only works if it is disconnected. Holding down the power button turns it off and then it tries to start, but again ends up with the garmin.com splash page that starts bright and then dims. I have tried the factory cable and one other. How do I get it to stop trying to connect to garmin.com/express. I have checked the garmin page and all seems OK and it is updated.

Without actually doing anything, the GPS is back to functioning normally. Thanks for looking into the problem. It might just have been a nudge to buy a new Garmin.