Interior Light

Hi everyone, I am fairly new to the Celica forums and have a question about the 02 Celica GT I bought about 3 weeks ago. Last night when we got home and exited the car, I noticed that after the doors were closed the interior light was still on. opened the doors again and the interior light switch was switched into the door position. After trying the doors and trunk again a couple of times but not succeeding, I climbed back into the car and clicked the switch into the center, which is turned off. Does anyone have an idea as to what this can be caused by and how to fix it?

Thanks

David