No, not a fuse size, instead its which one to piggyback.

After installing my Android Auto unit (great so far), I'm getting mildly miffed by the time it takes for the phone and screen to link up. Currently this is exacerbated by the screen powering on with the ignition only, i.e. the car has to start before the unit starts, then pairs etc etc.

I'm after a fuse t piggy back on that starts when the car unlocks, if possible, so that the unit can start up and start pairing with my phone before I even get into the car. Any suggestions for which fuse would be good for this?

Thanks.