back up camera troubleshooting

I have a 2007 toyota tundra with a back up monitor that went out a while ago. i asked the dealer to review the issue when i took my truck in for a scheduled maintenance and they said it would cost $800 to replace. It is not a necessity but it was really nice when it was working. I figured I would ask if anyone has completed their own troubleshooting on the back up camera? Id like to fix it on my own if i can but I cant seem to find anything on the subject. I don't really know where to start and I have not had any luck finding a replacement. it is the 2007 monitor on the roof liner just above the rear view mirror. Does anyone have any advise on how to trace this line, troubleshoot and test if it is a short in the wire, the monitor, the backup camera on the tailgate or the whole system in general? I appreciate the feedback. Thank you.

 

I'd start by checking any fuse to the system. If good then verify power is reaching the unit and go from there.

 

im pretty sure i can locate the fuse, but how do i verify power is reaching the unit if the fuse is good? thank you for the suggestion.

 

Does the monitor come on when you shift into reverse? Or does the screen come on but has a blank screen? Or does not power on at all?

 

it used to come on when i shift into reverse. now, nothing happens. Blank screen, no power.