Reverse gear signal input hook up help

I'm having trouble getting my reverse camera working it might be an issue with the power but I also need to hook up the reverse gear signal input and I'm not sure how to get it working automatically when I put it in reverse my stereo is a pioneer avh-x2700bs if you need that info

 

THere should be a wire for your reverse gear coming from the aftermarket stereo system that ties in to the reverse gear wire of the Tacoma. It sends an input to your stereo so it automatically displays when shifting in to reverse. The wire is located under the panel to the left of the foot pedals. If you remove the panel, it is a middle harness. This is how I pinpointed it: I started the Tacoma, placed the emergency brake on and put it in reverse and turned off the vehicle (so that the light comes on for the reverse light). I knew which harness it is located in because when I unplugged it, the reverse light wasn't coming in. This also has wires coming from the parking lights, brakes, etc. The reverse light wire is Red with a white stripe in the middle. I cut the wire and used a butt connector to re-attach and tie in the wire coming from the aftermarket head unit. Afterwards for good measure, I re-enforced it with electrical tape around the butt connector. It is a pain to get to when you go to crimp the butt connector with the crimper tool (depending on the size crimper you are using). Once it was done, I tested it before mounting the unit in the dash to make sure it works and it works like a charm. I hope this helps. I did a lot of researching and found nothing on how to wire it in, but some comments under a Youtube video and tried it and sure enough it was it! I hate splicing in to the vehicles wires like this without knowing ahead of time.