The headlight switch is part of the illumination control module. You should access the fuses on the side of the drivers dash. When you open the driver's door the side of the dash is visible and there are plastic screw heads you twist to open that panel which gives access to the illumination fuses. Open that panel and check each fuse. It you find a bad fuse you will know which circuit is giving you trouble. Repair that circuit.
If the problem is actually the switch then the entire module assembly will need replacing as it is not repairable.