I have a 8320R that has a 4600 display. The gps symbol kept dropping and coming back up. I just thought that’s the way it worked. I don’t recall it dropping auto steer but one day it completely lost gps and showed the receiver as not hooked up. For some reason I was looking out the back with the window open and noticed a connector unhooked behind the iso connector. I hooked it back up and receiver came back and it never showed the gps flashing again. There’s a terminator in the iso connector and without that it wouldn’t see the receiver. 

ps you could hook an implement to the iso connector and that will take that terminator out of the system. I have heard of the iso connectors going bad.