So the 2007 and other HHRs have a neat issue. When a tail light burns out, the Cruise Control stops working. But why? Well, it has to do with the brake switch and the signal from the tail lamps. If the computer can't see the brakes get turned on, via the signal from the lamps, it doesn't know about the cruise control cancel and will not allow CC to engage. Fixing the bulbs fixes the problem.