2013 Impala LTZ: My right low beam headlight went out. Figured it was the bulb. No big deal. Got the new bulb, plugged it in, and it didn't work. Tried the bulb from the left headlight which I know works and it doesn't work on the right. It's not the fuses, because I checked them and even switched them. So there's just something wrong with the wiring to the right low beam socket. How do I determine what the problem is?