Does your harness have a relay in it to witch on and off the fog lamps, or does the switch power them directly?

With the factory setup, there is a purple wire that connect from the multi-function switch to the car, and then a blue wire that connects the car to a relay, which in turn powers on and off the lights.

Here is a schematic of the OEM wiring with the multi-function switch. Compare it with the schematic of what you have installed.



If the extra blue and wire you have is the same as in the OEM set up, that is a output signal wire for the relay to turn on and off the lights, and the purple wire is the input signal wire to the car.

Is it correct to assume that your wiring harness is connected to a single connector wire that was taped up under the steering column? That is the voltage line to the fog lights.

All of these wires should be accessible from the white 34 pin multi-connector.