Keyboard Backlight Apple Macbook Pro Unibody A1278 13" US 2009 2011 Version
If your backlight isn't working well and/or has liquid damage, this can be the solution.  includes the super-thin LED assembly, the clear plastic "lightpipe", the vignette, and the bottom sheet with adhesive to hold it all in place.   Installation takes about 45-60 minutes, and is somewhat technical. No soldering required, but you'll need to remove your system's logic board, battery, and several harnesses to install.  instructions not included, but available online.