Fuel Gauge not working & blew a fuse (1973 Super Beetle)

[spectre1995]

Im relatively new to VW's and I'm going through some of the faulty electrical stuff (headlights and fuel gauge primarily) and I noticed the two nuts holding the yellow wire to the gauge, and the vibrator unit to the speedo body were missing. I replaced both nuts,turned the key, the fuel gauge started to work for about ten seconds, then I heard a pop and found the white #12 fuse (all the way to the right hand side) was blown. What sorts of things would cause this? I thought it might be the loose or dirty connectors so I cleaned up all the connection points and tightened everything up, and this happened.

Also, my low beams never work, and my high beams only work *sometimes* (seemingly at random). Does this sound like more of a ground issue, or possibly a faulty switch or bulbs?