New code: 556 Fuel Pump Relay

[justbinfishin]

So, I got my 118 code figured out. I still get it when it's extremely cold (-40 or less) on a cold block but that's because the ECT sensor is out of range. Now I'm getting 556 (fuel pump relay primary circuit failure). Obviously, there's something wrong with the fuel pump relay. How does one go about testing this relay if the relay good what else might I have to do to the problem? Could there be a fuse popped?

And could anyone recommend an electrical book for this generation of rangers?

Thank you!