The stalk is faulty. Can be striped but is easyer to replace. Use one from a PUG 406 as it is much cheaper and exactly the same.
Defective ignition switch.
check the headlight/multifunction switch
try unplugging the headphones and then switching it off it should work.
change ignition switch and/or tumbler
Replace your headlamp switch.
check for short to power in the circuit
A bad relay switch will cause the windshield wipers to not turn off. Replace the relay switch and the windshield wipers should turn off.
If you have two switches connected to a light in a room.example your bed room and you are in your bed you wont have to get out of your bed to switch off the light but u can switch it off by pulling a switch over your head.
check dimmer switch for headlights
Brake light switch went bad.
I have the same problem in my caprice, what you need to do is just sit there and switch it to high for a few minutes, then eventually if you keep playing with it it will turn off when you switch it to the far left
Were is the fuel shut of valve on a Citroen Piasso. Open the bonet and look on the left hand side on the top corner, there is a red push button switch. that is the fuel cutoff switch.