If you look up the bulb number, it shows them as 24 watts each. That comes to about 1.77 amps each at 13.5 volts. I looked for the fuse, but couldn't find a separate fuse marked "Fog lights". Figure they sized the wire for about double the load 1.77 x 2 (lights) = 3.54 amps (load). I'd try to keep the load under 4 amps on the fog light circuit. If you want to run more, trigger a relay off of the fog light circuit and run a heavier power supply wire.