2005 keystone sprinter

Ok, I have a weird situation. Getting ready to leave for the weekend and I noticed I didn’t have trailer brakes or stop, running and turn lights. After investigation I found that I had the ground (white) and my harness leading to my holding tank had been ripped to shreds, also found that the wiring to my slide out motor was broken. All appeared to be pulled on very hard. All wiring is protected by a under carriage cover. Looked at everything that could have possibly caused this. Just baffled! Anyone have any issues like this?