Did you check for voltage, anywhere? I know you checked fuses, but, did you check for voltage at the fuse. In the diagram, you see the drl relay and fuse. The bottom wire on left side of drl relay is ground controlled by the bcm. It has to be grounded to energize the relay. The bcm receives a signal from light sensor. At the moment, I don't know if there would be a trouble code for this, I'll have to check. Referring to diagram, you can check voltage.