Why do my internal speakers only work in Windows7/Bootcamp?

Running OSX Yosemite, I have no sound from the internal speakers, and they don't even show up as an option in the sound settings, just headphones show. The sound that comes through the headphones is horrible. I tried all kinds of things but gave up on it and have been using a Bluetooth speaker on my desk.

Yesterday I loaded Windows 7 using Bootcamp and while attempting to get the Bluetooth speaker to work I found that the internal speakers were working just fine in Windows 7/Bootcamp. The sound is great!

Any ideas how I can get the speakers to work on the Mac side?

Thanks!