I have a 1990 300D and the fuel door won't unlock. I pulled out the trunck liner and removed the amp (I think it is the radio amp). The fuel door lock has a round disk on the back and looks like I should be able to pull it to unlock the door. Nothing moves. Does anyone know how to unlock the door so I can get the locking mechanizim out so I can fix it?

Thanks
Dwight Hanson