It's probably the main relay. Like posted above, litsten for the fuel pump as soon as you turn the ignition on without turning it over. You should hear it hum for a couple of seconds. The main relay feeds the fuel pump power. If you can't hear the fuel pump, that's why it's not cranking. You can resolder the solder points on the main relay without having to buy another one. That's what i did. Search for main relay, and you'll find exactly how it's done.