Need to replace trailer end cable

[Rockinjwolf]

Hello, Need some advice. I think I have a short in trailer end cable. It was pinched a couple of times and now I have blown 30A fuses in box under bed . This only happens after towing so I think it has to do with movement. I found a couple of 7 way replacement cables on net. Question: does this splice into box under bed? And does box have to be under bed?! Seems like a strange place to get to for fuse maintenance. If it has to stay, can I splice or crimp or ?? Any help will be apprec. thanks, Jeff--oh ps TT is 2000 2570