I fully concur with the above if parts are broken. Well mine was bad moving the "lever" and got stuck or not. I took the whole "switch "assembly out and started to clean it with lack thinner then Silicon oil (NOT DWW ok! it dries out and sticks) .. Was a process of some 3 ..or may be 5 repetition steps and time (!) ..lack thinner silicon oli..loop
There was a lot debris and old sticky grease all clogged up..now the thing is working fine.
hope this helps
Mat