Where does the hot wire for aftermarket fog lamps get wired in? hoping to use one of the empty buttons on the dashboard.

check fuse--relay--switch-bulbs==use a meter to test switch connectors--wiring--sockets

What fuse blew ? What did you hook up to for battery power for the fog lamps ? What aftermarket fog lamps ? Hope you know you can't just hook up aftermarket stuff just any old where . Your best bet , take it to a qualified repair shop. Let them see what you did wrong .

Theory of operation. The bcm monitors the headlamp switch to know what is going on, the bcm then sends voltage to fog lamps, when activated. At the fog lamps two wire connector, the black wire is ground, the other wire is voltage comes from bcm. You can use test light to check voltage and ground with fog lamps turned on. There are codes for fog lamp, the two that I noticed, shorted to voltage or shorted to ground, these are B type codes, manufacturer specific. Check the codes.
I saw two 40 amp fuses going to bcm, those fuses are hot all the time. No specific fog lamp fuse because the voltage comes from bcm. Hope this helps a little. I can only help with testing.

Foglights are illegal in clear weather, so just leave them unconnected. People will appreciate the great look even when not on.

Check your fuses, a short will blow them.

hiya first thing u need to do is earth both negitive sides of the new foglights to chasiss of the car then with a test lamp find the positive switching wire at the rear of the original light and connect with a scotchlock or solder it to the two positive cables comin out the aftermarket fogs then you can switch them on useing your original fog switch it may need a bigger fuse

I have not run into this problem before. Usually, people either purchase the vehicle equipped with fog lamps from the factory or they add aftermarket fog lamps to the vehicle after purchase. In your case, you are trying to connect factory lamps that were not there from the factory? I'm not sure that you will find the connectors you are looking for. I do know for certain that the factory fog lamps are computer-controlled and that if the vehicle was not equipped with them from the factory, then the computer will not be programmed to make them work. If the wiring and connectors are there at all, they will be coming from the Totally Integrated Power Module (TIPM) located on the left fender. The factory wires are WHITE/YELLOW for the left fog lamp and WHITE/ORANGE for the right fog lamp. What about control switches,wire, etc. Did you purchase all of that as well?

If you accidentally grounded the hot wire, you probably blew the fuse...

2012 toyota highlander fuse box location Google Search

There may be a connection in the harness or a place to connect the cabling, but what you'll find out is that the light switch is different for the trucks that have fog lights from the factory. They have a pull-to-activate function for the fog lights and an indicator led on the switch that shows the fogs are illuminated.
I would suggest purchasing an aftermarket fog lamp kit with the entire package...switch, wires, relay etc..cheaper in the long run... not too hard to wire on these either...the toughest part is feeding a wire thru the firewall... but even that's not too difficult.
Hope this helps...

You have a short to ground somewhere in the drl-fog lamp circuit. Check for obvious wiring connector or wiring to drl & fog lamps. check wiring for pinched or broken wires coming from sockets. If you don't find problem, you can trace wiring from lamps to main harnesses and hopefully find source of short.
hope this helps.