To be honest I don't recall the wire color I tapped into (it's been a few years), perhaps someone else does. But I'm definitely sure it was a thin wire, and I had to use one of the smallest connectors (the little red one). I'd suggest some old-fashioned electrical troubleshooting. You'll want to use a voltmeter to see that you're getting good voltage and ground from your wire-tap and where you grounded it to the plate (which should be fine). If that's good, then you'll want to check the function of the gauges for which I suggest a known good voltage source (9V battery is the easiest).