The most common cause for malfunction seems to be the switches in the stalk themselves rather than the other components.
The good news is that, if this is the faulty component, you can simply swap the indicator stalk for another one.
You car is a later "DBW" (Drive By Wire) car and therefore this stalk swap is surprisingly cheap and easy to do.
In fact for cars that don't even have cruise control, the stalk is all that is needed to get it.
http://www.omegaowners.com/forum/YaBB.pl?num=1197646817The above link is a guide in the maintenance section which talks you through "adding" a cruise control stalk to a DBW car that doesn't have it as standard. This process will suffice for what, I believe, you should try as a 1st point of failure.