Hope so, it only seems to happen during wet conditions, so logically to me it must be moisture getting into connectors or p clip on t box chafing but turned out to be rubbing on the sharp edge on top of transfer box.
Fingers crossed this is the problem.
I really do think you've probably nailed it. Just need to reinsulate or put new wire in then wrap the heck out of it, heatshrink it, in decent tape etc. Best of luck.