When I first bought my car I noticed that while I could lower the rear driver-side window from the driver switch, I couldn't raise it. My first thought was a weak motor, however from the rear driver-side controls I can't lower the window, but it raised no problem.

That was in February. Now it just doesn't work.

I'm not horribly concerned, but would like to fix it at some point, however considering its odd functionality before it failed I'm wondering what exactly needs fixed. I was thinking the switches were bad, but both having the opposite issues for the same window seemed unlikely, so I'm thinking motor or wiring. Does anyone know for sure?