My 83.5 westy won't start.

A few weeks before nostart, there were random occurrences of an electrical
clicking sound from beneath or near the drivers seat.  The e-brake light
might blink.  The radio may have cut out.  Then it would be fine.  It was
worse around bumps.

One day it wouldn't start.  There is power to other accesories, and a cable
attached right to the starter produces start.

QUESTION:

What is the recommended fix for this problem?

I assume I should address more than simply the starter wiring. And I should
be removing the dash to replace my wiper arm thing soon...  thanks.

aaron in it's finally raining in wisconsin