1990 toyota corolla 40 amp fuse at positive battery terminal keeps blowing. on 1990 Toyota Corolla

40 amp fuse blows and the car won't start. The 100 amp and the 30amp are fine. What would cause this to happen and what does the 40 amp fuse go to?

Asked by for the 1990 Toyota Corolla
this will be a short circut or fialing component on this circut,vehicle should not be driven until this is repaired,short circuts can cause fires,you will need to find a shop taht specialises in electrical service,to minimize diagnostic charges