When I turn flashing light left or right, after passing through corner they are not automatically turn off. On the service they told me that I have to change the whole Switch unit steering column.

Is anyone having this problem, does anyone have the wiring diagram of inside of Switch unit steering column.

 

You have to change the entire multi-switch, sorry. Very common procedure on all car makes.

 

Sounds more like a mechanical problem than electrical. I haven't taken apart the steering column on my MINI but on other cars I've tinkered with there has always been a tab in the steering column that cancels the turn signal after completing a turn. Might want to take a look and see what's wrong and if it's fixable without buying a new combination switch ($500+). After looking at my Bentley repair manual, it appears you will have to remove the steering wheel before you can remove the switch assembly; however, if you remove the airbag you can see the top of the switch and maybe you can then see what's causing the problem. Good luck.