I think a long but flexible wire that you can use to fish the new wire down below is what is needed. Clutch control cables interior wire works well for this and most boat yards have some old one lying around from engine repairs. Failing that you are faced with either a complete removal of the pulpit OR making a new deck exit for the wire with a hole and cable clam and running the wire up the pulpit from there. No fun unless you get lucky with the "fish" wire!
No longer posting. Reach me by PM!