If you have a set of diagrams then you should be able to see for yourself what I was trying to tell you. Follow the wire out of the DRL module to the splice.
Consider this idea. What if a relay coil was wired into the parking lights? Then the fog lights were wired through the Normally Closed (NC) contact of the relay. Then when the parking lights were turned on, this would turn off the fogs.
Not exactly what you were thinking. But does accomplish the same thing.
2003 GT Convertible (sold & missed)
2000 GT coupe (Craigslist project. Fixed. Now my DD). Windsor to Romeo swap.