how to replace wiring for ignition switch?

Hi,
Actually replacing an ignition switch is easy, just remove the old and fit the new. The problem is that you have immobilisers etc to take into account. From experience I can tell you that Citroens are heavily tied into sensors and computers and modules (like most modern cars), so you must ensure that once you've changed the switch that your new key will work with the immobiliser.
Use the Citroen owners forum to pick the brains of people who have done the same job.

Cheers

westcountry
October 2013