I would just disconnect the pump and replace the fuse and see if it blows again. That will tell you if the pump is over amping the circuit. I would take the pump apart as much as you can to see if it is something simple. Could be fun/educational as well. I was one of the kids that took all his toys apart!

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Currently
1991 Mazda Miata 174000
1991 Subaru 189,000 Winter beater

got rid of:
1984 VW Vanagon 195,000
1976 350SE Euro 185,000 KM
1973 280SE 4.5 (boy do I regret that)
1980 280SE European W126 4 speed manual (miss it)
1989 BMW 735iL 119000 (good riddance)