Do you have a HOME THEATER device that shares speakers with the radio?
TRUE STORY: I drive (Once I fix it) A 2005 Damon Intruder,, House radio worked great but dash radio was iffy, sometimes no sound, all indications were that it was working but no sound.. Saved me much on haircuts (Pulling hair out trying to figure it out) finally I found a relay bank,, Many RCA type (Phono) connectors, all tight,, Kept thinking it it had to be either that or the power amp next to it. Failed to notice a couple of milk-white MOLEX multi-pin plugs just above the RCA plugs.
Pressed on one of the MOLEX plugs heard a sharp CLICK as the latches fell into place.. Worked 100% every since.
Home is where I park it!