Looks like you can get a factory camera for around $180 on Amazon:
https://www.amazon.com/Backup-BT4Z-1...J0Z8FCMK305WPM
I found this video about repairing a 2011 Edge backup camera, I don't know if it's the same as 2013:
https://www.youtube.com/watch?v=JGbnUzFixfM
This page has some troubleshooting advice that may be useful:
https://www.700r4transmissionhq.com/...ing-ford-edge/