88 ford f150 has 2 gas tanks first one quit working now the other has quit?

The gas gauge went crazy each time before they stopped working.Is it my fuel pump, and aren't they inside the tanks? How can I tell if thats the problem without having to take it to a mechanic? I'm used to fixing my own cars.

If you are used to fixing your own car you'd know what to do. If you would have fixed the first problem you would not be in the mess you are in now.

By "quit working", do you mean you're no longer getting fuel, or do you mean the gauge is simply no longer working? Makes no sense to say a tank quit working, unless it's got a gaping hole in it.