T-taps you really shouldn't use. Strip the wire you are tapping into then solder to it or poke a hole through the middle, put wire through the hole, wrap wire, then tape and zip tie connection. Fog lights usually come with a relay to switch on and off power. One side of the relay goes to ground and the other to positive to activate. Most headlights are positive switch so you can ground the relay and tap the other into the headlight positive for switch and use a seperate positive for supply power. You should'nt use the headlight positive for main power as it's only designed for the current draw of the headlights and not extra foglights.