I attempted to wire my aftermarket fogs to my factory switch but wasn't successful. Thought it was my not being familliar with electronics, but turns out to be a bad switch (whole other story).
Anyway, I'm not famillar with the PIAAs, but I had a set of Focuz fogs that came with everything including a relay.
If you have a voltmeter, you should be able to figure out which pin is which in your switch. Check for continuity between the pins with the switch in the OFF position. When you find the two that give you a reading, one of those is ground one is power. Now, with the switch in the ON position, do the same test using the pin that wasn't one of the two earlier (this is the pin that determines ON and OFF) as the "anchor" and test again for continuity. Once you've found continuity, you've located your ground. So, at this point, you will know what each of the three pins does.
Do as mentioned earlier to determine what each of the three wires from the fogs does, and wire accordingly. Note that if you have your fogs hooked up to use either your headlights or corner lights as a trigger, you will need to have those on to test for power.
Someone correct me if I got anything wrong here.
