Hi Sam
the thing to check with a bike of that age is where there are known problems with the wiring being damaged which can make the fuses fail.
The places to check are where the 2 bolts holding the rider's seat go through the frame brackets. The wiring is right behind the brackets and the bolts are a little too long, so can touch the wiring.
The other place is under the passenger seat, and look on the left side of the bike where the wiring runs round the edge of a bracket welded on the frame, towards the back.
If there is any damage to the wiring, you can usually repair it with some electrical pvc insulating tape.
