Originally Posted by
wetamup2k3g
According to the Haynes manual diagram I have in my hand right now, on the 8Ga the headlight switch gets its 12V from two fused wires; the red/black from the engine compartment gives power to the high/low beam portion and the black/white gives power to the parking/headlight portion of the switch. All the switch's outputs go directly to either the front ECU or the ETACS ECU. From there the front ECU provides the grounds for the control sides of the low- and high-beam relays, much like the PCM provides ground for the injectors. It's worse for the 8Gb; the low- and high-beam relays are inside the front ECU.
So if I were to wire the fogs to the headlights I'd use the actual headlight wires to power the relay for the fogs since I wouldn't want to mess with the ECU's at all. For your new relay to do what you want, I'd wire the 86 terminal to the actual low-beam wire on the headlight harness, 85 terminal to ground, 87 terminal to foglight wire to the factory foglight relay, 30 terminal to fused battery 12V. I gotta draw it out to see if you'd need a diode anywhere in there to prevent backfeeding anything, but so far I can't see you hurting anything.