[RuthleSSchevy]

Does anyone know the best way to use the backup camera on demand?

Would be nice to press a button and have the camera display, not just when in reverse. Is the reverse activation just a pressure switch, Whats the best way to wire this up?

[HyperBlue16]

Not sure, so take with a grain of salt and maybe use to look around for more info or someone else knows.

Might need a Mylink Hack/mod. Modifying the firmware, but then could affect warranty.
But i read on one forum for a different year/model GM, That when reverse lights come on, it activates the camera, he said a GM tech told him. SO maybe somewhere inline with the reverse power, you can locate the wire that goes to the system put in a switch, so one way the factory way works to get its power signal, and the other way it is getting your bypass power.

But again, until some schematics comes out or you locate more accurate information, don't completely listen to me.

[cellsafemode]

i'd imagine mylink wont display the camera unless it sees the car is in reverse over the data connection to the car's network. I doubt it's going to be a simple switch as the mylink head unit is also aware of when you are in park and the camera video is still displayed when you go out of reverse for a short period. All pointing towards a data connection and software controlled video display.