380sl steering wheel shaft upside down?

[jimsclub]

When I make a turn the turn signals do not turn off. I pulled the steering wheel and found the little zero mark that lines up the steering shaft is on the bottom and not on the top when the wheels are pointing foward. I think the shaft was installed upside down at some point in time. Is this a diy job or do I send the car to MB If it's a diy how do I do it?