Bad ground equals inop not over current to the gauges.
Just so you know... You are flirting with disaster. System voltage will kill either the limiter or both gauges. Hopefully the limiter will go ahead and die first. It might cook the gauges ruining their calibration before it dies or it might fry them proper. Current always takes the path of least resistance and most of the time that's the fuel gauge. So... fuel gauge or in some cases oil gauge dies first, followed by temp gauge.
