1977 fj40 Po spliced the white blue white in dash and connected it to one terminal on 30 amp ammeter. He then ran new 10 gauge wire from battery to other ammeter terminal Converting to 50 ammeter on new cluster. My understanding is I need to install 50 amp shunt. I want to install this under hood instead of under dash to clean up all the wires. I can trace one end of whit blue wire to fuse box but can’t find the other end assuming it is engine compartment somewhere. Any thoughts where it terminates?