Is there a fuse for the backup lights? My guess is it would be labeled "Back". If you can find this fuse you can use a fuse tap to come off it to power your camera.
Fuse tapA fuse tap is easy to use.
- Remove the existing fuse
- plug in the fuse tap
- Plug the existing fuse into the fuse tap
- Check the backup lights still function
- If no lights remove the backup fuse and plug it into the second hole on the fuse tap and check again
- once you have backup lights working again then use the second fuse slot to power your camera