So this weekend we were camping, and my battery was dead. No problem, I just borrowed my uncle's (at his suggestion of course) in order to use my tongue jack to hook the trailer up to the truck. His camper was working perfectly. After i put the battery back, none of his 12v stuff works (slideout, lights, etc...). He found both his 30A fuses in the panel (on the 12v section) blown. So we went to replace and as soon as he put it in, it sparked and blew. We then unplugged from 120AC and same thing happened, Flipped all breakers off, same thing happened. So whether he is plugged in or not, nothing running off 12v works. and as soon as he goes to replace either of those fuses, they spark (pretty badly) and blow. We then tried all of the above again but disconnected battery cable until fuses were in, then put cable back on, and blew the fuse immediately. I'm assuming since it still did it when not plugged into shore power, I can assume its not the converter? We checked to make sure the batter cables were hooked up right and the ground was solid, other than that, can't really tell too much about where the wires run. I feel like crap since this is obviously related to me taking that battery, so if anyone could give some help, I'd really appreciate it.