fabia front door light problem related with opening of fifth door

Hi Everyone, I'm a new member and have problem with my classic fabia... the sensor on my front drivers door dosnt work, when i open it, the interior light dosnt go. it is obvious that the sensor of the interior light located on the front door is not functioning properly. On the other side the fifth door lock sometimes doesn't open before opening one of the rear doors. Could anyone advise wether the microswitch of interior light in the front door is in relation with the fifth door problem and how? Would replacing the lock with the microswitch on the drivers door solve this problem? Could anyone help.