Replacing a BUSS fuse block with a blade fuse block
What is meant by "pass through"
Some circuits get power from a location, like the headlight switch, then go through a fuse then to the load.
Other cirs get the power from a common bus bar of sorts then go through a fuse then to the load.
Basically if you take a volt meter under the dash with everything turned off and the doors shut.
Some fuses have power and some do not, till you turn on a switch etc.
Some aftermarket fuse blocks have 1 or 2 busses that feed all the fuses.
You will need some spaces that are isolated from the buss