Solved my own problem. I switched over to a different template and it started working, there was apparently a script which was looking for an undefined element, (unrelated to the google search), and the error, for some reason was creating a conflict with the search box. I removed the problem script at the cost of a funky little background animation I didn't need anyway, and it works perfectly now.

If you're having trouble entering text into the search box, check your console for JavaScript errors chances are that's the culprit.