Fuel pump

Theres a break in the wires going back to the pump , or a connection is dirty, just use a perment jumper in line, and put a same size fuse in it, or take a mulitameter , and check inline wires to find the break , or replace the wires

Hello,

some vehicules also have; another fuse for the computer that control fuel pump another under the dash specific to the fuel pump, a relay,on fuel circuit and some have a switch that if there'se a hit it cut the fuel pump power to prevent the fuel to leak in case of an accident etc try to contact a isuzu dealer and ask a printed electrical plan of your fuel system it could indicate exactly what could cause the problem