What model year? Any prior wiring modifications? What do you mean by marker lights? - exterior parking lights, or interior illumination?
You most likely shorted the new red/green connection (which would be grounded with fog switch pressed) to positive feed for the foglight relay (red/blue) which would blow the 20A foglight fuse and ground the positive for illumination, possibly blowing illumination fuse as well. Have you checked the colors carefully on the foglight relay and replaced the fuses yet?