My 1995 Ford Courier had a flat battery one day last week and I lost my radio. When power returned I entered the wrong code five or six times so now all I get is "ERR" constantly. I have since found the right code but can't get rid of the "ERR". I have disconnected it again for an hour or so but still can't get it back. It's part no is ford96DA-18B865-AA, model is a FCTO14A2-A, serial no is 9962833 has no brand name on it as far as I can remember. Any help or advice?