I just did this upgrade. if you have power door locks and power windows then skip the aftermarket relay bit. if you have manual windows and door locks then follow all these instructions.
You will need:
1. the existing harness plugs (pinned up under the front bumper) and the removable blanks.
2. a new dash switch that has fog light option.
3. a set of fog lamps.
4. an after market relay with the plug in harness.
5. the stock ford relay to go into the "fog light" socket in the fuse panel under the hood.
Install the lights, under hood relay, and switch.
For the aftermarket relay: find the grey wire with the violet tracer coming out of the harness plug that plugs into the headlight/fog lamp dash switch. this is your power to fog lights lead. find the very thin brown wire over at the "smart junction box" behind the passenger kick panel. the brown wire will need to be grounded to turn the lights on.
now install the relay so the grey/violet wire powers the relay and the brown wire gets grounded when the relay is energized. Follow the instructions for the aftermarket relay to wire it up just do it to complete a ground instead of a positive circuit. Mind you instead of using the Relay to send Positive (+) energy to the under hood relay you are using to complete a ground (-) for the under hood relay to energize.
as a note: i tried to buy and install a new smart junction box so it would all work like factory; this will NOT work. Basically the main computer wont talk to the upgraded smart box so you have to go around it and a new smart box is $300+ vs an aftermarket relay that is $35. yes i went to Ford dealer and had them try to reprogram the computers and no it wont work... but a simple relay will, go figure.
Welcome Visitor! Please take a few seconds and 
