I'm looking for suggestions on what to check....
A friend of mine has a 96 250 with the diesel. He has twice now blown a 30 amp fuse that's located in the engine compartment.
I can't remember what number the fuse is, it's the top one in the fuse block. Whatever it's controlling it completely kills the truck when it goes.

Any suggestions??
Thanks

 

You have to ask yourself what is he powering off of this fuse for it to blow, is he trying to power some stereo? Is he trying to power some off road lights??

With a truck that old, I would bet someone somewhere hooked up some accessory that is drawing too much power...

If not he has one bad short..

 

From past experiences- there's a 30A fuse that powers the fuel heater in the fuel/water separator, if the heater circuit is shorted it will pop that fuse.

You can put a new fuse in it and unplug the connector (pass side square connector- 8 wires- attached to separator housing) to the f/w separator and then turn the key on.

If the fuse does not blow, the separator heater is shorted to ground.

Replacing the f/w separator will correct your concern.