I have done a lot of research on this also, and found that if you have the factory fog light plug in the dash 2 of the 4 wires are already hooked up. The black ground, and the red/blk illumination, but the blu/blk for switch on to the relay is not, neither is the tan/org for the led on indicator.
There are various ways you can wire your lights to work independently from the headlights, or to work with them as stock. You can also wire them to operate and shut off at anytime, or to only operate when the ignition is on, and shut off when it is not.
From the switch there are the 4 wires, 2 of which as stated above are already prewired, and 2 that are not. Those 2 wires will run through the harness and should terminate at the firewall connector. Your relay will have 4 terminals, 30,87,86,85.
30 goes to the battery or fused power always hot. 87 is output and will go out to the foglights and also run back to the tan/org wire for the led indicator in the switch. 86 will go to the blu/blk wire at the fog light switch plug, and 85 to a switched power source, or hot wire. 30, and 85 should have inline fuses in the wires used.
85 can be wired into your headlight circuit, or wired independently to another source for power like ignition source. When the relay is wired up, pin 86 acts as the ground from the fog light switch when on to complete the circuit, and turn on the lights.
So your configuration would be like below.