2000 jeep g.c.l reverse backup camera

I have a 2000 Jeep Grand Cherokee Laredo that I'm installing an aftermarket Backup camera from eBay. I've connected the correct wires to the tail lights reverse, & the video cable to the indash monitor.. But I've been hearing there is another wire that signals that I'm in reverse & turns the display on when I'm in "R".. I'm hearing that it's inside, at the drivers fuse box computer wiring system area, but not sure of the color wire, or how to get to the wires to make the splice to the reverse signal sensor.. Can anyone advise? Most appreciated if someone has the information.. Thanks..jgcl2000

Connect the Reverse Wire trigger from your Indash monitor to the reverse light power from the tail light. If you have to run the video RCA to the back where the camera is located, then might as well run a remote wire alongside and that is the sure fire way.