Speaker's own gps can hear everything, right. No problem.
If you take the audio output and aux input to connect the radio, also everything ok.
Even the music player can hear perfectly well.
If you pair the 660 with the Midland BT2, I hear the music perfectly but ... when there is a drawing instruction or whatever, it stops the music and not hear anything.
By the way, I made a hard reset to 660 and has not helped.
Of course you do not know if you have this configuration screen sound like me. I put a photo, but not look very good.
It sounds strange that Major appears as disabled and can not be modified. What you have also so you?