interior door lock/unlock button problem

[unclepauly]

hello,

i have a boxster W reg (2000). my problem is that the interior door lock/unlock button (the one on the dash with the image of a key on it) does not do anything. it DOES light up, however, when the doors lock automatically when i drive off. this means that when i come to get out the car, i cannot use this interior button to unlock the doors, i have to pull the door handle twice (first time to unock it, 2nd time to get out).

does anyone know what could cause this problem ? i have checked the fuse booklet but could not find a fuse for this button - am i wrong ? if so where is it ?

any help appreciated.