Hi Utuado
I dont't know if this will help, but here is somethings that could contribute to the problem you are having.
The light sensor should be faulty or dirty. But a dirty light sensor should give you lighter pictures as the camera should compensate.
The settings could be changes so you have a higher Exposure value (EV) resulting in darker photoes
There could be dirt or sediment on the camera sensor, blocking the light from being detected. You could follow the guide for repairing the autofokus, [guide|13008]
as you also here has to clean the sensor.
I hope some of these issues could be the cause of our problem :)