So Monday I was driving to work when I heard a thud as i was getting off the freeway and my 4.9L v8 base model deville started dinging and the gas reading E, i had just filled up before going to work...now i've driven it everyday since and just keeping track of my miles. The fuel tank door and trunk release buttons do not work. The dinging only occurs when i turn the lights on. The thud i am thinking was the float inside the tank to read the fuel level. I am hoping its just a fuse but hadn't had time to test them.