Is your fuse block corroded badly? The fuse blocks are pretty simple, and I don't think much can go wrong except for poor contacts with the fuses. If that is the case polish the fuse contact points and spade terminals. If your fuses or the wires connected to the block are not getting hot, there is not a problem.

From my experience the problem with these fuse blocks is the fuses. Many replacement fuses are poor quality. They look to be made of aluminum instead of the yellow metal of the original fuses. The aluminum seems to crack and collapse under the spring tension of the fuse block causing poor contacts.

I use original fuses if I can find good ones.