bleuquila

This is something that seems to come up pretty often, so I thought I'd post how I wired up my driving lights to do exactly what I wanted.
The lights are Hella FF1000's, and I removed the stock foglights and mounted the Hellas in place of them. I only use the Hellas if my high beams are also on, and so I wanted to be able to turn the Hellas off by using the high/low selector to switch from high to low beams. This makes it a one-step process to turn off the brights if you come upon oncoming traffic. I also wanted to have a switch in the cabin so that I could have high beams on, but not necessarily be using the Hellas at the same time. Since I had removed the foglights, I wanted to use the OEM foglight switch instead of the (IMO) ugly Hella switch.

The two wires that connect to the 85 and 86 terminals of the Hella Relay will be run through the firewall (using the hole behind the gas pedal) and up to the back of the OEM switch. make sure to mark which one is which before you run them through, as the FF1000 kit, at least, gives you a lot of green wire. At the back of the OEM switch, the Red/Green wire and Black/White wires are the ones that went to the foglight relay. Cut them, and connect them to the two wires from the hella relay that you just fed through the firewall. The wire from relay terminal 86 goes to the Red/Green wire and the wire from relay terminal 85 to the black/white.
The last thing to do at the switch is cut the yellow/blue wire and directly ground it to chassis. (I used a bolt that was located right nearby) This is necessary because that Yellow/Blue wire acts as the ground for the relay, but it's tied in to the low-beam switched ground which means you'll only have ground when the low-beams are on; exactly when you don't need a ground.

Now, back at the Hella Relay. Terminal 30 goes right to the battery positive terminal, make sure there is an in-line fuse. (The Hella FF1000 kit has a fuse built right into the supplied relay for you) Either a 15 or 20 amp fuse is good, depending on if you use 55W bulbs, or 100. Terminal 87 will split into two wires, one to each driving lamp.

The only thing left to be done is tap into the low-beam switched ground, which will provide your +12V signal when the high beams are on. You'll need to wire a jumper connecting the terminal 86 wire to the low-beam ground wire (yellow/red at the back of the headlights).

Any questions, feel free to ask, I hope I explained that clearly enough. The results are just what I wanted, the foglight switch is illuminated at night along with all the other instruments, and the bar on top glows green when the driving lights are on, same as how the foglights used to be.

 

bleuquila

This diagram shows how all the wires are connected.

bleuquila

I should mention that this was done on a 2003 WRX. This picture shows the wires at the back of the stock switch. Just gotta bundle up the excess wire and zip tie it up under the dash out of the way.
The orange and violet wires are left alone, those are for illuminating the button at night, so that functionality works just like it used to. The yellow/blue wire goes to a ring terminal and is then grounded to the chassis using a bolt to the left of the hood-release latch.