Did you get a display screen with it to get the make/model?
I would climb up and see about taking the camera off and see if it's hardwired or wireless. Mine was hardwired and worked off being in reverse; others are different I hear. Someone probably has more experience with them.
Mine came from the dealer already installed. Mine wasn't working and I had trouble finding the inline fuseholder buried in the basement within all the wires. It didn't have a fuse in it and once I put a fuse in there, it kept blowing, at which point I finally figured out it was a bad camera. Took it back to dealer and waited 3 months to get a replacement at which point I figured out the wife was a better backup camera and haven't used it since.