91 F150 4.9 single tank. Also, is there a way of testing it or should I just replace it before I pull the fuel pump? The inertia switch is not tripped and the fuel pump doesn't turn on with the ignition. Thanks in advance.

 

The relay is located on the driverside fender well with the test connector close by, if you dont have an under hood fuse box. If you have the under hood fuse box then it is in there. If no fuse box, then it will be paired with another relay for the computer. The price of a relay and ease of change, I would change the relay first and see if that fixes your problem. If not then start pulling the tank and looking at connections etc. before replacing pump.