Gauge shows full all the time. Pushed the LP gauge switch. Had 12 volt on both the terminals on the back of the gauge. ( Both the red, and white wires are not connected to the tank sender. ) The white wire at the tank, But not connected to the tank sender. Is a true ground to the body. Next I need to engage the LP gauge switch to see what voltage I have at the red power wire at the tank. Shouldn't the voltage at the tank be lower? If I have power at the tank. Attach the ground to the ground terminal on the tank. It should work. If not. I need to check continuity in the sender. Bob Dunahugh 78 Royale