On my 2009 that 3rd hole is the inverter 100/400W control switch.
Yes, they were already there (taped to the inside of the fender up behind the headlights). I was able to reach them from underneath (lying on the ground).On the topic of adding the fog lights, where did you find the connectors for the fog light bulbs? Are they wired and ready to go, just tucked away somewhere?