Here’s install instructions for Diode Dynamics fog lights. Some good pics as to what the harness should look like. It says compatible with Eco models so I would assume the harness with the fog light taps are there.
Mine is a Mach 1, so a little different, but also does not come with factory fog lights, so somewhat the same.
First right up front... You mentioned a switch. The headlight switch unit contains the fog light switch. You can get the fog light version for about $35 - 50 on ebay IIRC. That switch is a momentary signal to the BCM to turn the lights on or off. Be careful you dont get a European switch... it'll still work, but also has a switch for rear foglight, which is a whole nother tree branch. Your car should have the wire from the switch to the BCM, as my Mach has it and its not even an available option. Look for a gray wire at pin 14. Theres also a gray at pin 11, dont confuse em. You need that gray at pin 14.
Next, the wiring harness at the BCM. On the Mach 1, it does not have these wires because it isnt even an option. Your car may have them since it is an option. Check connector G (lowest forward) for wires in positions 12 & 5. Those are outputs to the fog lights. If they are not there, you can buy wiring pigtails to install them.
The wiring connectors at the lights are all the same, hopefully yours has the BCM wires going out to those connectors.
Last, there will be some changes to make in ForScan. Most are in the BCM to turn the fog light function on, then to control how they act. Theres one change to make in the IPC to turn on the indicator in the dash.
Or you can just by an aftermarket harness, drill a hole for the aftermarket switch and slap it all in there. Do not try to adapt an aftermarket switch harness to the BCM for a part factory / part aftermarket solution. That could get really expensive.
I really like having it done factory style in my car. Hopefully yours is as simple as buying a switch and lights and doing some ForScan.