i took D HAG's MOD one step further.
what i did is got the same diode i used for the lows and highs. (3 amp, 50V resicitifer) and put it on the fog and high beam fuse just like the low and high beam fuse. so when ever my highs are on my fogs are on.
I was planning to do this, as well. But first I gotta get some decent fog lamps that are worth turning on. The stock 27-1/2 watt fog lights aren't good for anything more than decoration.
I put up another thread for a solution, but no one has the answer I wanted, which is a number for a 55-watt or hotter bulb to fit the stock fog lamps. So aftermarket it will be. Then I'll wire in the fogs.
I'd love to modify the fogs so they are ON with the headlamps unless I specifically turn them off (just the opposite of the stock setup). Making them always on with the headlamps would be easy. Being able to also switch them off is another thing. One of the few endearing features of our previous Ford Exploder was that the fogs were great, and the pushbutton switch for them was on/off, not a momentary like in the Tahoe.