Fuel Pump not working?

Hello, yes the fuel pump control module should have a 12-volt power feed, but also a control wire from the PCM which is going to be a pulse width modulated signal, which is a square wave on/off signal, so you may only read around 6 volts with a multimeter because the meter will only be able to average out the voltage reading. There is also a wire that the PCM monitors the fuel pump control module on, the OEM diagrams are showing a violet/green wire as the 12-volt feed from the fuel pump relay, a brown/white wire which is the PCM monitoring wire, a yellow/orange wire which is the PCM control wire to the FPCM. The outputs to the actual fuel pump are yellow/grey (output- fppwr) and white/brown(return-fprtn) and those 2 output and return wires will be shielded by a black/white ground going to the FPCM. I'll post this OEM diagram for you. If this FPCM is located under the truck near the spare tire like they usually are, I would also check the connector very well for any corrosion inside, it's the worst place to put a control module. It looks like a 6-wire connector, is that what you have?
And this looks to be a high-pressure fuel system, do you have direct injection with a high-pressure fuel pump with steel lines in the engine compartment?

Okay, glad you got it started. This is the OEM diagram for the FPCM and the PCM, the wires labelled FPM (Fuel Pump Monitor) and FPC (Fuel Pump Control) are going to be those pulse width modulated signals, VPWR is the 12-volt feed from the relay which sounds like it's more of the issue you're experiencing. But verify the Ground wire is good and there is no green corrosion where it attaches to the frame, I would also check any other Grounds from the frame to the body, those are sometimes the braided type, and can look okay, but still have corrosion which will cause intermittent issues with starting. I like to see those braided types replaced with a solid high gauge ground strap instead of those braided types.

If the voltage at the plug was down to 10-volts, that's no good, you need a solid 12-volts there. Modules never act right with a low voltage situation.

Glad to help, hope all goes well.

Yeah, apparently, it's not a serviceable component. Which is a really bad design. Service info states its 0.5hr to replace it but I can't see how that is possible. I would check with the dealership and see if that's really the case. If the entire Battery Junction box (BJB) needs to be replaced for one relay, I'd try taking it apart and check for a broken or cracked solder joint inside the BJB. When it comes to situations or modules like this, I'll always take them apart and try to fix myself. But if you look also at the control for the FP Relay, it's a Ground side (N-Channel) Mosfet chip inside the BCM. A Mosfet is basically a high-power transistor. I would check this circuit before replacing the BJB.

The yellow/violet colored wire (pin 24) from the BJB connector C1035A is the wire that should be grounded for the relay to turn on. If there is any voltage drop (high resistance) on this wire through the BCM, that is limiting current flow, that might be the problem. And not the FP relay.

I would find connector C1035A, it's probably located on the bottom of the BJB, there is one other connector that looks the same, but its missing pins 21-24. So, you'll have to ID the connector by its wiring colors and pin locations.
With the connector still plugged in, Back probe pin 24 and with a multimeter on DC volts, measure from pin 24 and battery negative while the fault is occurring.
When the BCM is supposed to be Grounding the FP Relay you should read close to 0 volts, If the BCM is not able to fully ground the relay, you'll read some voltage drop on that wire to battery negative.

Since Fuse 75 is hot at all times you will read battery voltage on pin 24 until you turn the key On. Voltage will be coming through the FP Relay until the BCM pulls that control circuit to ground. Then it will read 0 volts.

I just don't want to see you replace the BJB and the fault still occur. Technically you could ground that pin 24 wire and the FP should kick right on, because that's all the BCM does with that Mosfet, it just makes a path to ground through it. But check for voltage drop first, see if there is any when the relay is not turning on the pump.
I added the aftermarket diagram last just to simplify the circuit, if you have any questions before the test, just let me know.

Set the multimeter on a lower DC voltage setting or auto if it has it. It may only be a couple volts of voltage drop, but may be enough to limit current flow, relays don't take much current to turn on, but I've seen mosfets burn out many times.

One other thing, since Fuse 75 feeds both sides of the FP relay, you aren't hearing the FP Relay click, it can't be because there's no power to it, you're probably hearing the PCM power relay click. If you look on that OEM diagram, with Fuse 75 out, there's no power to that FP relay at all. So, something else is going on.

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Let it sit overnight, if it's an issue on one of the circuit boards, its most likely going to be a thermal hot/cold type of fault.