My LS alternator has 2 wires. The one large lug goes on the back and to the battery, and then I have a 4 or 5 pin plug that has only 1 wire in it. I'm going to run that to the warning light bulb in the gauge. If you're using an LED bulb in your gauge, you may have to put a resistor inline (270 ohm I think?) I needs to see some load to excite the charging circuit in the alternator. Someone correct me if I'm wrong. I'm trying to do this off memory. I have a diagram that's at the shop I can post a picture of when I go by there this weekend if you need it still. Some alternators have 2 small wires in that plug, and they wire differently. There's a good picture on ls1 tech of it somewhere.