Okay...
I'm trying to find someone else who has had this prob. - but have yet to find such a person.
89 F-150 with straight 6 (Y engine code)

Fuel tank switch actually caught on fire on me yesterday afternoon, destroying the switch and melting good part of the harness.

I replaced the switch, and re-wired the harness by hand since there was no local means of acquiring a new harness quickly.

I can switch between the two tanks now and the gauge reads accordingly between the two tanks - but my fuel line isn't pressurizing...

I have replaced the hi-pressure external fuel pump and fuel filter, and fuel pump relay - the relay harness was slightly melted as well - but appears to be usable.

I turn the key to on - and can hear 3 clicks - the first coming from the fuel pump relay - the others i can't determine alone.

Switch appears to be working correctly, and fuel pump relay harness has constant power on yellow, and power one brown when key switched to on.

It doesn't appear that my hi-pressure pump has any power though.

Inertia switch was not tripped, and truck was running beautifully up until switch shorted out and burnt.

I was trying to run the front tank dry so i could drop it and replace the filler neck which i believe is leaking -- i can smell gas from front tank and it leaks when parked with front facing downhill -- and the tank would have been extremely close to empty at the time of the switch fire - but truck was not cutting out yet...

If i disconnect the the gas line into the hi-pressure fuel pump - gas flows freely, but gas doesn't flow out of the hi-pressure pump.

I don't think I am getting voltage to my hi-pressure fuel pump -- assuming I am testing correctly -- I disconnected leads from pump and plugged directly into digital volmeter; I get no voltage reading even while cranking.

Any suggestions on a troubleshooting path from this point -- I really want to fix this myself and avoid taking her into a shop...