So, I was installing a dashcam in my 2011 Fit involving splicing the backup camera's wire into one of the reverse lamp wires. I did so, stripping a bit of the wire and twisting into it the camera's wire. (I'm no professional but I did follow a tutorial on YouTube). Wrapped it up in electrical tape, reinserted the wire connecter into the lamp, reconnected the car's battery and turned it on... only it didn't turn on. No sounds. Only the dashboard flashed. I freaked out thinking I'd spliced the wrong wire and potentially destroyed the wiring system. So I undid my work and thankfully the car works fine again. Did I splice into the wrong wire? It was my understanding the white/gray wire was hot and the black grounding. Manual doesn't care to explain colors. I followed a diagram I found googling the Fit's wiring schematics. I humbly request anyone's knowledge and experience.

 

It's possible you're connecting the wrong wire from the reverse camera, and/or that wire is shorting out to something. I don't remember the wire colors (I did this several years ago) but if you have a multimeter, it should be easy to locate the wire that's switching on and off when you switch to reverse.