Had the same problem on my xsara and seems to be a common problem with Citroen after the car is a few years old.
The indicator/light arm is easy to remove as there is only 2 plugs going into the arm unit which are the indicators (nearest the steering column) and the lights and horn. The unit and arm is one piece. You'll need to get either a new replacement arm and unit (around £80 new) or take your chance with a second hand one (around £25).
You'll need a star bolt screwdriver to remove the plastic panels that cover the ignition housing. The arm unit is sealed but could well be old grease that is shorting out the circuit. Remember to extend your adjustable steering column if you can to get it out easier. Good luck!
Paul
July 2008
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