if i remember right, they have 3 wires,. one goes to the battery but needs a high amp fuse, that will protect the alternator and your truck, that one goes directly to the main fuse box and from there with a high amp fuse to the battery(s)
the other wire , smaller one or thiner, that goes to the fuse box too , but that one serves as a voltage monitor for the voltage regulator,
the other one is the malfunction indicator, you just need a little light bulb and a 470 to 500 ohm resistor connected in paralell with the light bulb,. one terminal to a switch +, and the other to the alternator,. that easy,.