Skoda fabia door contact point faulty how to i check and repair?

my fabia's interior light doesn;t come on when the drivers door is opened, it does when the passenger door opens. Also the lights on buzzer is not sounding. I am thinking that the door sensor on the drivers door is faulty. Has anyone got any thoughts on this? Do you know where the door contact is and how i can check/ change it?|||it is in the bottom of the door jamb near the sill covered by a rubber boot it is an easy fix the switches are about 拢5 from skoda , vw or audi, it will also affect the immobiliser and locks