Steve
The wire in #3 position, on your idiot light harness, should be brown, it connects at the bulkhead to a brown/white wire. You can clip the brown wire. You must leave the brown/white wire. It connects to the ignition switch and to the voltage regulator, it is a resistor wire and is needed for proper operation of the alternator. The brown wire was for the alternator idiot light. You will need a new wire (or use the brown wire) in the #3 position, it will connect to the bulkhead at location *T D, from there it will connect to the horn relay. The wire in #4 position will connect to the bulkhead at location *S D, from there it will connect to the “Junction Block“ located to the right of the radiator, near the battery (main power feed from the battery). You should use a #20 fuseable link on both under hood connections for the amp gauge, available at NAPA. The factory used a black/white/dark blue wire for the #3 and a black wire for #4, both #16 wire.
* The bulkhead connector is marked with columns A B C & D and rows S T U V W X Y & Z.
The Amp gauge does not carry current. It is a volt meter scaled in amps. It measures the voltage drop from the "Junction Block" to the horn relay (on the factory harness the #4 wire, black\white\dkblu is connected to a soldered junction between the alternator and the horn relay) .5 volt drop is aprox = 40 amps.
The wire in #3 position, on your idiot light harness, should be brown, it connects at the bulkhead to a brown/white wire. You can clip the brown wire. You must leave the brown/white wire. It connects to the ignition switch and to the voltage regulator, it is a resistor wire and is needed for proper operation of the alternator. The brown wire was for the alternator idiot light. You will need a new wire (or use the brown wire) in the #3 position, it will connect to the bulkhead at location *T D, from there it will connect to the horn relay. The wire in #4 position will connect to the bulkhead at location *S D, from there it will connect to the “Junction Block“ located to the right of the radiator, near the battery (main power feed from the battery). You should use a #20 fuseable link on both under hood connections for the amp gauge, available at NAPA. The factory used a black/white/dark blue wire for the #3 and a black wire for #4, both #16 wire.
* The bulkhead connector is marked with columns A B C & D and rows S T U V W X Y & Z.
The Amp gauge does not carry current. It is a volt meter scaled in amps. It measures the voltage drop from the "Junction Block" to the horn relay (on the factory harness the #4 wire, black\white\dkblu is connected to a soldered junction between the alternator and the horn relay) .5 volt drop is aprox = 40 amps.