Read a thread a while back talking about 'ground switching', particularly on headlight circuits. Can't find the post. Question: on my 96, is it ground-switched? Also, tell me again the easiset / bestest / simplest way to identify the low beam wire to use to switch auxiliary fogs...
Not my area of expertise - maybe the diagram on this page at Slee's site is of help? It expains 'ground switiching' (seems that there is always a hot lead at the light and they only go on when the ground in complete?) and, more importantly, allows you to buy the wiring kit you need to make it all work (at $40, seems like good value unless you know what you're doing)
While this wiring diagram is for the high beam, you could use the exact same approach for the low beam circuit with fog lights. If you installed a 3 way switch instead of the regular fog 2 way switch you would have (1) off, (2) on with low beams and (3) manual override to turn fog lights on. To find the low beam circuit, you should just be able to trace the wires starting at the low beam light.
Given that I have't done this (yet), it is a bit of a guess.