Have you checked the wire runs from the fuse box to the base of the mast?The problem could be in that run. If that run is OK, IMO you should think about putting a junction box inside the
hull at the mast base where the wires enter. That way when you next remove the mast you don't need to cut the wires. Also when you cut the wires at the mast base you can test that
power is getting to there at least.
How did you test the fittings? If the bulbs are OK and the wires to the mast base from the fuse box are carrying
current, then, yes, you have to change the mast wires.
To change the mast
wiring, you will need AT LEAST 2 people
Method #1
- send someone up to the top with the new wire spool (agree tinned copper is best)
- establish that the old wire/s are movable & intact
- join the new wire to the end of the old wire SECURELY
- feed the wire down to the mast base
- join it to the old wiring from the fuse box at your new junction box
- open a cold 4X
Method#2
- join the new wire at the mast base & pull it to the top
- join it to the old wiring from the fuse box at your new junction box
- as above
If the wire/s are broken inside the mast you will need to send a messenger venetian blind chord attached to a weight down the mast & hook it out with a coat hanger or if you know a surgeon, a vaginal sound or a long pair of artery forceps are ideal for this activity. I find such items of kit to be invaluable on my
boat.
Alternatively to the hassle of the messenger chord, if you have at least one intact wire you can join two new wires onto it and pull it through.
I would NOT replace the wiring in the mast if the short is discovered not to be in the mast. Just fix your immediate problem and GO SAILING. If it ain't broke, don't fix it.