IggysCRV said:
Any accessories should be on their own circuit period. If something in that camera should fail or short out you may melt or fry factory wires requiring more work. I could have a camera installed cleanly in under an hour. It’s not hard to tuck wires above the front edge of the headliner to the A-Pillar pop the pillar cover off and run the new wires down the Pillar zip tied to the the other harness avoiding anything interfering with the side curtain and right down to the fuse box. Find a continuous hot and an accessory hot and use a tap a fuse to add the new circuit. That way if something in the camera fails it will pop its own fuse and not have any effect on the factory harness. Just find one of the higher amp fuses to do the tap a fuse on as its wire from the fuse panel to the battery is heavier wires. Anything above a 15 amp is fine to tap into at the fuse panel. Anything less amperage will still have tiny 18-22 awg wires feeding the fuse. And. Is no better than tapping in at the overhead.
I’m sure many will disagree and say tap into the dome/ map light harness. But I’ve just seen too many melted wires of people tapping into factory harnesses. Plus the wires are so small using a Posi Tap would be the best method not a splice or Scotch Clip. As they will simply cut the wire and you will now have insufficient connection to both devices. The Posi is a good tap but think how little that tiny point on that tap to the wire is making the connection.
I could ramble for hours why it’s a bad idea.
Again just my 2 cents here. It’s your car you can do it how you want.