Instrument Dash Lights
That black wire is on the ground side of the amp gauge .
YIKES VERY POOR WORDING. The black ammeter wire IS NOT GROUND and DOES NOT GO TO GROUND. It is HOT HOT HOT at all times and connected DIRECTLY to the battery through large gauge wire
It might be called the "load" side of the ammeter
HOW AN AMMETER WORKS. An ammeter (current measuring meter0 is in SERIES in a circuit.
All accessories and loads and the alternator are connected to ONE side of the meter (BLACK)
Only the battery is connected to the other side (RED)
Be VERY careful with the ammeter wires. The ONLY protection for the ammeter wiriing is the fuse link which is not dependable protection.
DISCONNECT BATTERY GROUND
So far as improving the ground to your cluster, run a pigtail wire from a ground point on the cluster and bolt to the dash frame or column support
