I'm sure this can be done but I think it would be much simpler to disconnect the factory wiring and wire the foglights to it own relay and switch..
My Opinion
Hi everyone,
:headbang: want your fogs to come on independently???
I found this link that is for the 2007 toyota 4runner but thought that it might be applicable to our vehicle as well. Anyone with some wiring diagrams and knowledge willing to take a deeper look into this and see if it is possible?
toyota indepedent foglight modification allows the use of the foglights without turning on the headlamps, Hi/lo and I think auto mode works also
Anyhow, here's the linky poo
http://www.top4runners.com/ja/2007/fogmod.html