my left indicator on my ford focus comes on on it own and wont cancel?

[mary]

I have a Ford Focus CMax TDCI2000 2006
The left hand indicator keeps coming on on its own and wont cancel then it suddenly cancels and wont do it for a while the more mileage you do the more it seems to do it
The Mechanic has had it today but it wouldn't do it

Please Help

 

[ALANtttttttt]

sound like something in the indicator arm is contacting when it shouldn't

 

[mmTheQueenHasSpokenmm]

My Neon would do that. If I turned on then off the emergency flasher it would stop. Give that a try.