When I did my headlight retrofit, I custom wired the inside headlight harness for the functionality that I wanted it to have with all my extra goodies. I put led bulbs in the projector housings for the fog lights, but it was a very back burner project
Now that I wired the gauges in and ran stuff through the firewall, decided it would be a good time to run the fog light trigger wires and such too.
On the euro switch, fog position 1 will be headlight fogs, and pos 2 will be the in bumper amber/yellow fogs. I could have been done, but I decided I didn't want relays all over the place. Plus I already have some extra wiring from my morimoto harness, the under hood lights, and the addition of a BEW lift pump.
I ordered an auxiliary fuse/relay box and am going to send both sets of fog lights throught relays in there (even thought both draw such little current). Its got spots for non relay fused power as well, so I'll send my under hood lighting to there as well. Headlight ballasts im going to keep directly connected to battery power (and the ground) just for peace of mind. Fuel pump power I'm not sure if I'll keep it directly to battery or go off the new aux box, I'll make a game time decision.
Aux box is supplied by 2x 12ga wires. I'm going to install an inline 40a breaker between batter pos and the aux power since the 2x 12ga wires I'll tie together in parallel can safely handle that. The side going from the battery to the breaker will have 8ga which can also handle 40a.
So for some reason if something goes bad, the individual circuits are all protected by fuses and itlf it goes really bad, the breaker will trip (it's resettable)
I don't plan anything with massive current draw to be on this car, so 40A at the same time is plenty. I think the bumper fog light bulbs I have draw like 3A if that, and the ones in the actual headlight housing are around 1A. The under hood lighting is about 1A, the fuel pump is (?). I'm well within the parameters.
I'll post a couple pics when it's all said and done.