I was wondering about wiring a amp gauge into my cluster, on the wire hook ups on the back of the gauge it has a "+" on one and a "-" on the other, so I assumed hook it to the pos and neg on the battery, but this just popped the fuse, so when i looked again i noticed it had on one side "+" and under that "Bat" and the other is "-" and "ALT" so "+" would go to the battery pos post, but where would the "-" go on the alt??