Driver's side brake light not working, not bulb
 

I have a 2012 Elantra, and the driver's side tail/brake light isn't working. The turn indicator light still works fine. I've replaced the light bulb, but that did not fix the problem. Any suggestions on the next thing I should look at and how I can test the components without going out and buying unnecessary replacement pieces?

Thanks!

I presume you are saying the taillight for the left rear is not coming on,, correct?

yes, that is correct. Left rear side.

You would need a test light or voltmeter to confirm power is getting to the lamp in question.. If you found power was not getting to that lamp socket, then you trace the wire back and keep checking for where the power is lost.. It could be a broken wire, poor splice or connection .You may need to go all the way back to where the power is sent out to the lamp.
If the one side works chances are pretty good the non working side is spliced into the same supply That would most likely be inside the trunk/vehicle . You might need to open up a harness to get to the splice.