Dumb question- battery switches...

[JVM225]

That’s a new one on me. Guess anything is possible.
I’ve installed dozens of stereos over the years and never came across one like you describe.
Usually the memory (yellow) wire is for the presets/clock to be remembered in case of a power loss to the main power to the radio not to supply power for the radio to play.
But if the OP isn’t sure about using his radio he can do the same with a cockpit light or similar 12 volt item.

 

[atrick]

It supplies power for the memory for all the presets for the stations and when you loss power to that you don't have stations and it won't let you get one. Don't remember the brand name but it was put in by the previous owner and its a sirius radio but other than that it works great just took awhile to figure out how he wired it up plus he has it wired from the back off the battery switches, with fuses so if the battery switches are off you still got radio and it doesn't really draw enough to worry about running batteries down if left on. Its a first for me on the wiring and radio too.