Chosen Solution
I have the same issue: “My Keyboard Lights won’t light up and my F5 & F6 keys don’t do anything and I dont have the options of lights on my keyboard settings anymore” I just took off my back cover and noticed a small flat cable with black tape disconnected from my board just above the battery. I attempted to reconnect it but there is not a way (clip) on the cable itself to connect it to the board however, it does look like the clip used to be on the wire is missing. I’m guessing this is the light sensor cable and most likely the reason for my issue? Update (07/30/2016)
Logic board with clip missing from backlight strap
Here’s the IFIXIT guide to replace the logic board: MacBook Pro 13" Unibody Late 2011 Logic Board Replacement. Use it to reference the cable you are speaking about. Its possible the connector is broken and someone used tape to hold the cable in place. If you can take a tight picture (in focus) of the area and paste it into your question (edit mode) so we can see what you have.
