Is it broken? They can break at the pivot point.
Is it just dirty? They corrode and can be disassembled and cleaned. Inside are copper contacts that can be polished clean with Brasso or other metal cleaner, put a little di-electric grease on them so they don't recorrode, reassemble and it's as good as new. mark what is top of switch and body. Take pictures before you take out contacts so you know how they go back in with out having to think about it.
Do that same with the headlight switch while your at it.
Wouldn't hurt to do external contacts and contacts in plastic block if you want to be thorough.
- - -TR7 Spider - - - 1978 Spitfire- - - - 1976 Spitfire - - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra - Yellow TCT