I modified it differntly from Jkmotor and actully found it much easier. GO to radio shack, Get your self Two 50 watt 3 amp resistor DIODES. Open your hood, go to your fuse box, find the fog lamp relay and your low and high beam relay.
Its a bit fuzzy in my mind but for the low and high mod put your diode on the RIGHT REAR hole and smash your relay back in, then put the other end in the highbeam right rear hole Smash that relay back in, I think the grey band goes towards the highbeam relay, but im not sure, Now if your highs come on when you just have lowbeams then the diode is backwards.
for the fogs, find the fog relay, the stick it in the 80 hole (lables in the corner of the relay guide found on the back of the fuse box lid)
then in the RIGHT REAR of the highbeam relay, again grey band towards the grey.
With it set up like this your fogs will ALWAYS be on when ever your highs are on. YOU CANNOT TURN THEM OFF WHEN YOUR HIGHBEAMS ARE ACTIVE!!! but you still have full control over them when your lowbeams are just on.
THIs was some time ago i did this. Please look back at JKMOTORS thred and look at the last 2 pages, where the instructions were given in a more detailed form with pictures.
GOOD LUCK