The light sensor is located up under the black plastic cover around the rear view mirror mount. from the outside of the vehicle, look at the rear view mirror area. you should see a purple / blue square (2" x 3") that is the rain sensor, right beside it should be a small clear round circle this is you light sensor. in the day light with the car running, place a dark piece of tape over it and you lights should come on. as far as the fuse goes...sorry don't know.
hope this helps