I've seen this done for radar detectors all day long. I am looking at adding a dash cam using the power from my rearview mirror using a similar method.

I don't know the exact power needs off the top of my head, but I know the current power cable has a 2amp fuse. They make mini-usb adapters that match the rating of the power cord, I just need to know if the 12v power at the rearview mirror can handle the additional amps.


2009 F150, with auto-dimming rearview mirror.

Thanks for any help.

 

I looked at the rear view for my radar detector but decided to utilize power from the light fixture in the headliner and also installed my ground there too.

 

I ended up going a different direction with it. It hated any power adapter that wasn't OEM. I wired in an extra cigarette lighter socket off of my fuse panel, plugged the car adapter into that and ran the wire up through the pillar and headliner. Basically the same process, just needed an extra wire.