For those who has dimming mirror, you can hook up this small dc-dc converter to the mirror harness and mount it with 3M double sided tape to the back of the mirror. I used "12" 3 Pin Connector PC Computer Fan Extension Adapter Cable, Black Sleeved" $2.99 from ebay to make it removable. Open converter cover to get access to PCB. Cut cable in half and then trim to 1-2" on female part to connect to mirror plug wires (I solder always) and 4"-5" male one half to wire to the DC-DC converter 12V pins. Then cut the original USB wire appropriate length ~6"-7" and solder to the 5V output pins in the DC-DC converter. Use glue gan to secure wires in converter, close the cover. So no need to route the wire and find fuse. Mirror is already fused with 2A and activates when ignition is on, so it is more than enough for both mirror and dashcam.
Leaf 2015 SV CPO traded for 2019 Hyundai Ionic Limited