Had the same problem on my new Santa Fe after various visits all parts replaced turned out to be a software fault they reset computer with a new patch whatever that means and had no problems since (5 months ago)

 

Just bought a 2007 Hyundai Sonata, less than 24,000 miles. Great condition. One problem: cruise control does not appear to be working. The switch to turn the "cruise" light on works. But then when I press the Cruise Set button, nothing happens: the "set" light does not appear on the instrument panel, and the cruise control does not function. Any ideas out there in Hyundai Land? I am posting this on August 16, 2013

 

Did you read post #2 in this thread?

 

We have had the same problem on several cars and the cruise switch resolved the issue.