I'm not sure, but I don't think the software would affect the AM/FM reception.Its a RER model with sat, nav, and uconnect capabilities and the back up camera. Just happened three days ago. FM and AM signal comes and goes. Everything else works fine. Don't want to take it to the dealer if its going to be a quick repair. Current software application is 9.713.
A bit more info? Did it just happen? What year is the radio? It might just need an update you can get them here http://mofv.com/mygig/ . If you want to check the antenna i would start under the fender. Then look at the back of the radio.
Black is the AM/FM. Yellow is Satellite radio. Blue is GPS.