somewhere i found a link that explained that, when you install a fuse tap, you have to install the stock back, and another of different amps, but a little bit lower capaciy, and the place is critical. 1 has to go at certain place (over or under) and so the other.
problem is, i cant find that link. by any chance you do? (or anybody out there?)

edit: found it: he says that the 1 on top has to be smaller. see around 7 minutes.