rear brake not working...could use some advice...

Hi guys. I am new to the forum, but not to riding. I have just picked up a 2003 sv1000s with 6500 miles on it. Its never been down and its as clean as it gets. On the ride home, i noticed the rear brake was really weak and then it gave out completely. (40 miles to home). I have since inspected it, and there is break fluid, intact break pads, and its not leaking anywhere. The brake light comes on when pedal is depressed, but the pads dont engage at all. It just sinks all the way to the bottom. I have a feeling it wasnt ridden that much with only 6.5k miles on it. I have searched for the answer through this forum but couldnt seem to find it. I am wondering what to try next?