Possibly the switch is broken internally,
.... if so, no option - replace.
Had similar problem, - the switch was simply stuck, - 1 tiny squirt of WD-40 solved the problem immediately.
Talisker, August 2010
I am assume that the switch is stuck this is often a problem when you get high humidity the switch components swell so if its not clicking on and off that may be the problem
Gmac, May 2010
If the string is broken - fit a new string
If the switch is broken - fit a new switch
If you're unsure then pay a qualified tradesman to do it for you.
