Common problem, I've got 3 that have died out over the past year. The bulbs die out around 40k or sooner it seems. You can buy new switches for about $55 online part #68057595AC or if you want to replace with LEDs here is a great write up with photos.
LED Light Upgrade for your Power Window Switches
2011 JKU Sahara; Sahara Tan, Leather, 3.73, Auto, Hard/Soft Top, SpiderWebShade, Dead Pedal, Skid Row Foot Pegs, BFG KO2, 10a Wheels