I'm looking at a few pictures of the engine compartment of this year Sonata and I'm not seeing any boxes. Can you upload a picture of where the sound is emanating?
Disconnect one of the plugs wires by grasping it near the base of the plug and twisting while pulling. Next, if you have a #2 Phillips screwdriver, insert it into the plug boot until it makes contact with the electrode at the bottom of the boot. Hold the screwdriver in the boot 1/4 inch from a good ground and have someone crank the engine. You should see and hear a strong and bright blue or white spark. If not, Use a meter to see if the coil is getting power.
Check out the images for the ignition circuit troubleshooting steps.
Images (Click to enlarge)
Monday, October 10th, 2011 AT 6:53 PM