The electric fuel pump system consists of two fuel pumps: a low pressure boost pump mounted in the fuel tank, and a high pressure fuel pump mounted on the frame rail.
On vehicles with single fuel tanks, the electrical system, provides power to both the fuel pump relay and a timing device in the EEC module. On vehicles with dual fuel tanks, the electrical system, has a fuel pump relay, controlled by the EEC module, which provides power to the fuel pump under various operating conditions.
The Fuel Pump Relay is located under the plastic shield at the air cleaner support bracket
First verify Voltage at the Relay on the YELLOW wire with Ignition On & the BROWN wire.
Then verify Voltage to the Frame Pump & wires going into the Tank for the Pump
Also, be sure the Inertia Switch has not been tripped:
the Inertia Switch is located at the far Left part of the toe-board, near the parking brake assembly.