1984 GL1200A radio issues

[SIR tricky]

If you have any electrical accessories maybe you could disconnect them one at a time to see if any of them are a contributing factor

Do not be afraid to dig into the left pocket, yes it looks like a rats nest of wiring in there but once you become familiar with what everything does it does become second nature.

I haven't come across a problem where neither of the controls worked at all , only that they became sluggish and required spraying with contact cleaner.

All the radio wiring connects eventually through the connectors on the left inner side of the fairing and sometimes these do get corroded over time, tough to get out but the do eventually pry out with a screwdriver.

Check em out.