Gauge Installation on a 6.6L Duramax

Close up view of Yellow Ignition Switched Source.  Using a test light or voltmeter, check the wire you have decided to use for your 12V+ Ignition Switched source.  Ground the test light or voltmeter to the chassis and check the wire with your test lead.  You should have 12V+ with the key in the ON position, and no voltage with the key in the OFF position.  Notice: 2 red wires inserted into wire tap connector.  These 2 wires are for the pyrometer and Trans Temp gauge.