I'm assuming the truck won't run and you checked the pump already. You can try in this order to see where problem is.
Check the following contacts when you key to run (not start) for a 12v signal which may last less than 2 seconds so you will have to key each time. Leave key off for at least 10 sec between.
Check from A to ground, this is the hot being controled. If not 12v then look at fusible link to battery.
Check from F to D(ground), this should be the signal for the relay to turn on. If not 12v then pull off the connector and check the wire to ground for 12v. If not 12V then your problem is towards PCM, may be the wire. Don't forget to reconnect plug before moving on.
Check from E to ground, this is the "output" or pump side. Can be hot from PCM control if cranking or cold, or oil press switch if engine is warm and upping pressure. Relay is only need mostly to start eng, press sw will keep the fuel pump hot after.
You can check if applying 12v to C will run your pump. First check to see if 12v is already there. If so the relay is staying open and may be stuck if the F to D was 12v. If no 12v at C, try applying it, and if pump runs relay is probably bad.
There was a contact on the ALDL or DLC that was good for this but I forgot which one it is. I will try to find that.
WARNING: This was mostly from memory, but I threw it out there because nobody else has jumped in yet. Good luck. I'm hoping you wanted the gas one not the diesel one.