Did you ever put the radio to a ground? I didn't on mine at first because I thought it was built into the harness but it was not. It worked sometimes then I hooked it to the ground and bam works like a champ.
The jeep is just about the easiest radoi I have ever installed. IF you can pull the radio there will be probably a black wire just sitting in the dash that needs to be connected for aftermarket radios to work. On the amp did you check the connections there along with the ground on that? Were is the inline fuse running to the amp at from the battery that might have blown.
milemarker 8k,junkyard lift w/ skyjacker nitro shocks,smitybuilt bumper, kc daylighters, auburn ected d30, 34" swampers, new project dana44 hp and 9" axle swap with 4.88/locked f/r , new new project full traction 6" long arm...
ok try looking at your security wires or your remote wire they could have come loose and also inside the headunit will be a fuse if you are willing to look there your self.
in my past audio builds in car sony has been the ones to play up for no reason if you want a cheap good headunit go for like an alpine they are easy to use and worth it