OEM Fog Light Switch, wiring... Options

[UTSlickVic]

Well I'm installing my OEM Fog Light "push" Switch I got on ebay- Switch located beside diver side vent. Its of of a ST202. I figured its alot cleaner look than after market switches. Anyways, I ran into some confusion on how to wire it. There are four wires. But the wiring (not stock) leading to my fogs now only consist of 2 wires- well at least from a quick glance under the dash. However, the wiring was from after market fogs (later I just hooked up OEM fogs using the same wirring) came with a light up switch (which I did not use). So I think the wiring has capability of lighting up a switch (I think).

Need some direction...

Does anyone know what each wire does? Can I neglect a couple of wires?

here's a pic of the OEM wiring from the button.

[Hanyo]

there are 4 wires

wire a: ground
wire b: parking light ( so the switch lights up at night)
wire c: postive for relay
wire d: neg. for relay

only way to tell is to use a volt meter and measure the values of the wires.