2003+ 6.0L Powerstroke wire sources.  Arrow #1 (red with yellow trace) is where to connect switched ignition power.  The 2 wires that get connected here are connected via a wire tap.  The 2 wires are from the pyrometer and trans temp gauge amplifier boxes. NOTE: We are now supplying a Yellow (larger) male connector for this connection.  Arrow #2 taps into the instrument lighting power (Light Blue with Red tracer or Yellow with no tracer wire, 2nd from the top left on the large grey connector) Arrow #3 is where to ground pyro, trans temp, and gauge lighting wires.
NOTE: There are many different locations where you can obtain your ignition switched 12V source and your dash illumination. Depicted above is just one example.  Irregardless of where you connect your gauge power and illumination source, we recommend that you check these sources first, before you make your connections.  For 12V Ign. switched: Using a voltmeter, ground the black lead from the meter to chassis ground. With the red lead off the meter, probe the 12V Ign. switched source.  You should read 12-13VDC when the Ign. key is turned on, and 0V when the key is off.  For the dash illumination: probe the red lead of your voltmeter probe the suspected dash illumination source.  With the running lights off you should not read any voltage.  When you turn the running light on you should see the voltage rise and fall with the adjustment of the dash lighting.