Join Date: Aug 2008
Location: Whitstable, Kent, UK
No inline fuse as far as I'm aware.
Dodgy/dirty switches is the prime suspect.
Get some WD40 into everything, split the RH switch cluster slightly, stick the nozzle in and give it all a good blast moving the switch back and forth. (or take it right off the h-bar and do it properly, maybe even gently sand the contact points and coat with vaseline before reassembly).
Then do the same to the LH switch while you're in the mood.
AVOID trying to disassemble the switches themselves on a whim. tiny fragile bits that love to hide.