SS has provided me with a wealth of information and know how so I thought I'd contribute my share to the forums.
I number of people on the forums have problems with their turn signal intermittently stop working flashing while trying to signal. This happened to mine too so I decided to investigate the problem as there was no solution except to replace the unit.
VADIS says it's necessary to remove the air bag and steering wheel but this isn't necessary. There’s three TORX screws below the steering wheel cover and the two pieces are held together by clips. They come apart without putting up a fight. Hint: Try using the steering wheel adjustment hole as a starting point to unsnap it. Do NOT undo the wiring thats in the way of the top screw on the stalk. Move it out of the way gently. I'm not sure if that's the SRS wiring but I doubt you want to find out.
Sorry I didn't take more pictures of the internals of the lever but I'm sure you guys can figure out the clips. Gently pry with a flat head screw driver and it comes apart nicely.
It turns out that the area where the signal lever's pins contact the PCB is covered with grease and contaminants thus breaking the circuit.
Inside the assembly there’s a circuit board. There’s a slider with three pins for the turn signal and the high beams. For me, the right turn was the one causing problems and looking at the following picture, I can understand why. The pins gliding over aren't making a good contact with the board.
Simple solution: I wiped away the grease with tissue. A quick look with a magnifying glass shows the pins haven't worn through the pad and the volt meter says the proper connections are still intact.
In my case the solder pads haven’t been worn through. If it has I'm sure a very thin layer of silver solder would do the trick.
Hope that helps!