Gauge Installation on a Gen 3 Dodge Cummins

This is a picture of the headlamp switch connector after it's been disconnected. On 2003-2005 models the illumination wire is Orange with a Brown Trace or Orange with a White trace on the top row of the headlamp switch connector.  On 2006-2007 models the color is Orange with a Brown trace.  There may be more than one wire with the same colors.  Before removing the plug, test the wires with a voltmeter or test light to identify the correct one.  Turn your parking lights on.  With the test light you should see the light get brighter and dim with the adjustment of the dimmer control on the factory headlight switch.  With a voltmeter you will see the voltage rise and fall with the adjustment.  Turn the parking lights off and test again.  You should have no reading.