NOTE: I don't own a Gen3 so this is just general theory.
WARNING: Work with electrical wiring at your own risk. Follow these ideas at your vehicles own risk.
WARNING: Once you locate the parking light Hot and test for whether the Fog Light use a combined Hot or each Fog has its own Hot by using a test light or DMM, it is important to disconnect the Hot to your battery so there are no HOT WIRES.
The quick and dirty way is to install a relay in conjunction with the parking light Hot line. The minute the parking lights come on, the Fogs go on and since the parking lights remain on in all other headlight positions so will the Fogs.
I like a relay that is rated 5 amps over what the fog lights pull to keep from overheating a relay. Also you are going to use most of the wiring from the factory fog lights but it is key that you make sure that the current Hot line and any hot factory relay line are removed from any relay currently controlling the Fog Lights (what you don't want is a possible ground loop or a unconnected wire going hot when the factory lights are in a specific position once things are disconnected).
So buy the proper rated relay, find the hot parking light wire and use a Scotch clip to tap it then wire the Scotch clip jumper to the control input on the Relay. Wire the main hot input to the relay to the battery and ground the main ground input. Wire the factory fog light hot that has been disconnected from the current factory relay/switch (the actual wire going out to power the fog lights) to the new relay's Hot Output side (I like Double Pole relays so that each light gets its own hot line direct from the battery when the relay is activated). Also depending on how the factory fog lights are wire, one might on need one hot to power both, but only do that if that is how the factory wiring is. If there are two hots, one for each Fog, DO NOT ATTEMPT to feed them with a single Hot!