An update on my f150 no start

So first off I have to say this customer has been excellent to work with. I'm still trying to get this truck to start. It's been on the back burner the last two weeks with me being ill.

Any way I got back to it today. I studied a wire diagram a bit more and thought hey why not bypass the relay that Ford installed that I can't service. So I did just that I put a power wire at the connector that comes out of the fues box. It's at this point that the fuel pump circuit starts. No luck.

I then went to the fuel pump and found I no longer have power there. If you remember I did have power earlier hence the reason for the fuel pump change.

So back to the fuse box to confirm power. And yes there is 13 volts (battery charger is hooked up to eliminate low battery).

Well the next easiest thing to check would be the fuel pump driver. No problem. I unplug the connector. I have continuity for the ground. I also have 13 volts on the power coming in wire. Hmmm do I not have power making it through the driver?

So I got out my wire piercing probes. Hooked one in to the wire that feeds the fuel pump. Plugged the connector in... No power. Ah ha no power is making it through the driver. So I thought I best check my power from the fuse box wire. So I hooked my other wire probe into that wire and... No power. GRRRRR WHAT THE HECK. I just had power there. I unplugged the connector and my fuse panel power come back. Once I plug the driver back in I loose the power.

So my question is guys do you think I have a bad driver even though it's new. It's a dorman brand and a few people tell me to get Ford parts.

Could I have a relay that can't handle the load once I plug the driver in and is tripping so to speak?

If the driver was shorted to ground would my multimeter show that as 0 volts on the fuse box wire?

The plug on the driver has 6 wires. You have power in, a ground, power going to pump, power coming back from pump, and 2 wires from the computer that control the speed of the pump hence maintaining your fuel pressure.

"2 wires from the computer that control the speed of the pump"
This is what I would checkout.
When you unplug it, it could be resetting, then when plugged back in, it is tripping a relay in the computer. Could be something to do with the fuel safety shutoff.

If it was shorted to ground I think it would blow a fuse.  If you want to be sure, remove it from wherever it's mounted.  That would probably your path to ground.  Get a couple of jumper wires and jumper the power in to the power out to the pump to see if it works.

again, remember during your checks... You only get power for 3 SECONDS when you turn the key to the ON position... then the computer shuts it off until the motor starts.

Edited by steve(ill) - 16 Mar 2020 at 6:01pm

the light at the driver will tell you if you have constant power ( with your other lead to GROUND)... If you do, then you need to connect to the pump and see if it will run... or if the problem is NO GROUND ( possibly from computer?) .......... now if there is NO POWER at the driver then YEA.... your looking at the relay or the wiring.