First check both fuse #'s 22 (ECM (Electronic Control Module)) AND 35 (Fuel Pump). They both have to be good.

If they're good, then to figure this out you have to pull the fuel pump relay and test the sockets with a test light.

But 1st, after pulling the relay, Use the test light or multimeter to make sure that there's power at the relay socket corresponding to Pin 87 on the relay map.

If there is, (to take the PCM out of the equation), just jump the relay sockets corresponding to Pins 30 and 87 on the relay (they're diagonal from each other on the relay socket). The fuel pump should run. (You've checked and have power at socket 87. Socket 30 goes to the fuel pump.).

If it doesn't run, check those fuses again to make sure 1 didn't just get fried. (maybe a short in the wiring between the relay and the fuel pump)

If they're good, then go back to the fuel pump's electrical connector, disconnect it, and check for 12 volts in the connector. 

If you have 12 volts in the connector then the issue is between the fuel pump wiring connector and the fuel pump.

If you don't have 12 volts then the issue is in the wiring between Pin 30 on the relay socket and the fuel pump.

But what if the fuel pump ran? Well then, since you've already bought a new relay and know it's good, and you just determined that the "Load Side" of the relay socket is good, it's time to test the "Control Side" of the relay socket.

Those are the relay sockets corresponding to Pins 85 & 86 of the relay socket.

Here You Can't Use A Multimeter alone. You have to use a Test Light.

This is a "power side control relay". The PCM energizes the relay coil by sending 12 volts to it. The relay coil's other side is always grounded.

So in this setup, the PCM still sends a "bias voltage" to the relay coil even when it isn't energizing the relay coil.

It isn't enough amperage to energize the relay coil. (the computer uses it just to monitor). But it will read as 12 volts on a multimeter. So using a multimeter can fool you. The bias voltage isn't enough to light a test light.

So on the Control Side sockets, PIN 86 is constant Ground. Pin 85 is powered by the PCM to energize the relay coil which closes the internal switch between Pins 30 & 87.

So use the test light to make sure Pin socket 86 is Ground.

Then check Pin socket 85 for power from the PCM for a few seconds after you turn the key to ON. 

The PCM provides power to Pin 85 for a couple of seconds after the key is switched to ON to prime the fuel system.

So here's a picture of your fuel pump relay with the relay pin map on its side. (Don't worry about Pin 87a it isn't relevant to this).

After the picture, I'll post a video of Paul Danner performing these tests on a 1999 Chevy Suburban. The actual problem is different than yours but he explains how to do these tests. Your relay and relay socket are the same and you should watch it to get a better grasp on the relay circuit and to confirm the socket pins on yours are the same as I've explained.

https://www.youtube.com/watch?v=McnXLcJNVfI

You've already replaced the relay and fuses, maybe the pump itself is bad? See if you can check the fuel pressure without opening the gas tank and exposing yourself to the fumes, though you should be able to hear the fuel pump priming itself when you turn the key.