Reverse Gear Signal Input on Pioneer Head Unit

I'm installing a Pioneer ND-BC6 backup camera on my Tacoma. On the back of the Stereo (Pioneer AVH-P8400bh) there is a wire that's labeled "Reverse Gear Signal Input." Any thoughts on where the best place to hook this wire would be?

 

See your post in audio video, my reply was wrong.

 

This should technically work. It just wants a 12v signal saying that the truck is in reverse.

 

I was thinking about doing this but thought there might be an easier way to hook it up to a wire closer to the gear shifter or fuse box.

 

Have you pulled the shifter cover, the safety switch/reverse switch may be there, I haven't a clue.

 

I'm going to do that today if I can't track down a wire more accessible by the fuse box. Wish me luck