Originally Posted by Dave N

First off, I want to give credit to TheW3r3w0lf and Fountainhead for information they provided in this thread: Daytime Running Lights + Switchback LEDs Their info was very instrumental with the development of these instructions.

This DIY will allow you to wire up a set of switchback LEDs for use as DTRL on pre-2013 Z's. The DTRLs will be active when the ignition switch is in the "ON" position but they will deactivate when the running lights or headlights are turned on (whether the headlights are set to auto or manually turned on). This set up can utilize the existing dual filament bulb or switchback LEDs (wiring differences will be detailed in the body of the DIY).