I think this is the solution. The red is how it is hooked up now and the blue is how I propose to hook it up. The LED will only get power when the diff lock switch is engaged and won't illuminate until the diff lock detection switch closes completing the circuit to ground.

<img src="http://home.off-road.com/~kemanuel/forum/WTF2_thumb.jpg" alt="" />

Click here for a larger, more readable picture.

2000 4Runner | 5-speed | E-locker | Tundra/OME 2" lift | Stubbs Sliders | Deckplate/TrueFlow |