2004 expedition xlt no crank no start-started by checking fuses. When checking the top row, all were good but light on test light was very dim. Checked all other fuses -all were good and light was much brighter. I don't hear the fuel pump turn on when I turn the key. I was told fuse 34 is usually the culprit and that it will test good because some how it back feeds through it. I pulled that fuse, it was good I pulled the fuel pump relay looks like one slot is kinda melted. But without the relay, and WITHOUT #34 FUSE, truck cranks over. Won't start because no fuel. Put fuse back in, truck no crank no start......what the hell?

 

First,,,, When you test a fuse it is either good or it is not , there is no way you can get back feed .
Did you check if the inertia sw is tripped ?
Because there is a drop in power available to the vehicle most things electrical will not work.
What you need to do is check and trace from where power comes into the fuse panel and out to the circuits affected.
A poor connection OR a partial short in the system can pull voltage down where many electrical/electronic things will not work.
The melted connection is the result of something pulling more current than it should OR poor high resistance connection
When you turn the key on you should hear the fuel pump run for1-2 seconds.
The PCM provides the ground for the fuel pump relay for that 2 seconds. If it does not receive an RPM signal it allows then relay to open, as long as the engine is cranking it should be providing that RPM signal..From your description of the melted relay connection, there could be a shorted path thru the inertia sw on down to the fuel pump or a problem with a seized fuel pump.
If you unplug the connection down at the fuel pump , turn the key on if starter now works, problem is fuel pump. If no change , problem is with wiring..