I avoided solving the electrical mysteries left by the previous owner of my Volkswagen bus for years. This handy Blue Sea Systems 6 bladed fuse box came along and helped me organize, if not solve, my problems.
If you read the Samba's Vanagon forums you'll rarely hear a positive word about 'prior owners' or the dreaded PO. I actually kinda like the guy who sold me my bus. I am less appreciative of his talents or decision making as an amateur electrician. He did some great stuff, like installed the auxiliary/house battery kit to protect the main battery from draining while I'm camped, but he didn't wire over things like the stereo or lights. Why install the gear and not move the appliances behind it?
I figured the best way to solve the 3-4 niggling weird electrical issues was to rewire all the "house" equipment he or I'd installed through its own panel, one clearly behind the main battery's safety solenoid. This Blue Seas box is the perfect answer. Two larger terminals for hot power from the solenoid and one for ground (you don't really need ground in a car, but I it is handy for organizing wires into one place and would be great on a boat.) There are 6 pairs of smaller terminals for your gear. The box takes standard automotive style blade fuses, so you can pick the right size for each gear item.
The fuse panel didn't solve my problems, but it organized them and moved the electronics to where I can safely use them and not get stuck with a dead battery (I also keep a solar panel around, in case.)