Posted this at the end of another thread, but thought I would make an official how-to so it doesn't get lost...
How to wire your HID fogs(see end for regular bulbs) to come on with the parking light switch...
I am not responsible for you blowing fuses, setting yourself on fire, or anything that happens when you do this...
I did not include the easy steps like connecting a ground wire or a power source...
The parts I used...
2x 4 pin 30 amp relays
2x inline fuse holders
6x wire taps
8x female spade connectors
10 mm wrench
1) Disconnect neg & pos terminals from the battery.
2) Use a wire tap to tap into the orange wire in the pic shown here. (It is right next to your headlight)
3) Use wire taps to tap into the input to your HIDs. This will have one black and one red wire that your stock plug that your normal fog light bulb would plug into normally.
4) Connect the ground to your HIDs to a good ground of your choice.
5) Connect a short ground wire near the headlight. (I used the black bolt that holds the headlight down.
6) Use your inline fuse and connect to the power lead to the battery.
7) Run all these wires to right behind the headlight and crimp the spade connectors onto the 4 wires (from battery, orange wire, fog pos, ground)
8) Connect the wires to the relay as follows...
30 - 12V line from battery
85 - Ground
87 - Output to fogs
86 - Input from tapped orange wire
[img width=576 height=768]http://a.imageshack.us/img198/708/photo0041mf.jpg[/img]
9) Wrap it all up in electrical tape and repeat on the other side. Everything is the same on both sides!
To make this work on stock halogen fogs, instead of tapping in to the HID wiring, you would CUT the wires going to the bulb, run one to the ground, and run the output from the relay to the positive of the bulb.