Does the vehicle have day time running lights? If it does, that fuse is for them as well. Since they would come on right away, I'm questioning if there is a ground related issue. Can you tell if the fuel pump is working when the fuse is in?
The only thing I can think of is a ground related issue. Unless, someone has wired things differently. How does the rest of the wiring appear to be?
Let me know.
Joe
Sunday, March 1st, 2020 AT 4:30 PM