Auxiliary radio controls

I have a problem with the auxiliary radio controls in my 1994 Taurus GL.
The system is a JBL Radio H 18806 AM/FM stereo/cassette electronic with the
auxiliary controls on the dash for the driver. The three (3) buttons “scan” “-vol +” and
“mem” don’t work except the – vol + works intermittently. What can I do to fix
this annoying problem?

i had the same problem on mine. i found that the buttons were sticking. mine has a scan button. when you turned the radio on it would not stop scanning. i took the aux buttons and cleaned them. also wd40 where plastic meets plastic so it dont hang up there