Ford have a reputation for using similar parts throughout their entire vehicle range, I noticed that your truck is a 1986, in the mid to late eighties in the UK the Escort and Fiesta range of cars suffered from cheap and nasty fuse boxes and Ford wanted double the price of the original for a replacement.
You mentioned you thought it was something overheating and cutting out, I agree, I also noticed you mentioned the idea of hardwiring the pump, you must have been reading my mind.
I would hardwire the pump temporarily just to keep the truck running and in the mean time try and track down what to me is a joint over heating and breaking down, my first thought is the fuse box but knowing Fords like I do i wouldn't rule out anything. Start by checking the ground points all the way back to the main harness.

You are going to have to replace the ignition switch, these usally burn out and will make internitten contact test the switch for power out to the fuel pump relays, also this is a well known problem on the 93's otherwise i would check your harness under the truck im almost positive your ignition switch is bad please rate -jeff

If you are getting fuel, your pumps are working, your fuel filter is clean, then try going back to basics. Is the fuel clean and good. Are your plugs good? How about the wires and the distributor? Does the truck start at all? Need more description of what the truck is doing besides dieing. Does it shudder? What kind of sound does it make? Have you checked to make sure all your fuses are good? I can help but need more detail. But your best bet is to start from your ignition and work your way to the fuel pump checking for electrical shorts. Then check from the starter to your distributor. Double check that ditributor for hairline cracks.

Replace the pump with an inline fuel pump. its easier and u can hear it working plus you can run it to the fuse box to a fuse that comes on and shuts off with the key. its easier to put in and is an assured way to make the truck run again

I think it is fuei ignition or the combustion problem  check them....................

At the pumps unplug the wire harness and see if there is power there if not go over all your relays and see if there is any shorts if not there will be a electrical problem some were,,,,if there is power there check and see if its putting the right volts out

I had this problem on a full size f150 check your negitive battery cable there should be a a small wire comming from it . this is where they pull the negitive and it can be intermittent so make sure it has a good connection. . if that is not it you have a hard wireing problem and have to chase it down.

Check the voltage at the wirings coming to the pump, if the pump keeps blowing, then there may be a wiring problem, for example a short that damaged the pump after replacement.

The fuel filter...?