Check the wires under the relays, that is a problem spot on your truck.
The EEC (ECM) Power relay does send power to the coil of the Fuel pump relay when the key is turned on.
The Computer will then ground the other side of the fuel pump relays coil to close its contacts. The computer will ground this fuel pump relay for one second when the key is turned on and then again when the engine is cranking or running. To bypass the computer just ground pin #6 of the EEC self-test plug and turn on the key.
The power for the fuel pump relays contact common comes from a fuse link at the starter solenoid battery side. The output contact goes to the inertia switch.