The 15A fuse for the left lamp is #40 and the right is #41 in the IPDM E/R (or, "Intelligent Power Distribution Module, Engine Room"). If the fuse is good and you are still under warranty, I would suggest you schedule an appointment with the dealer as this is much easier diagnoses with a Nissan Consult III scantool. Your headlamps are controlled by the Body COntrol Module (BCM), which receives input from the headlamp switch and then commands the central processing unit within the IPDM E/R to turn on the headlamps. The relay for the headlamps is built into the IPDM E/R and Nissan considers the relays in the IPDM E/R non-serviceable and replacement of the IPDM E/R is required if one if its relays is bad. The "diagnostic flow chart" involves doing circuit tests between the switch and BCM and between BCM and IPDM E/R.