Navigate to a page where the data element is available on the site.
Open the web console and type in _satellite.getVar(‘dataelementname’) and hit enter. This code returns any value that is present for the noted data element on that page.
If the data element is working correctly, then the value is defined.
If the value is undefined, then the data element is likely setup incorrectly. Check the custom script for syntax errors.
If the value is null, then that data element does not have a value on that particular page. Try testing on another page before altering the data element setup.
If there is an error '_satellite is not defined', there is a scoping issue. In order for '_satellite.getVar()' to have access to the global _satellite object, check the box 'execute globally' in the script editor.
For more information on troubleshooting data elements check out the troubleshooting guide here: adobe.ly/1jTAzh7
You can also try the free DTM plugin developed by Adam Haining. It opens up a separate window with a full easy to read list of all of the rules, data elements, and _satellite.notify() comments. It gives you a complete list of all of the Properties Data Elements, the value for each if one is set, as well as its Type. Very handy tool! This plugin is MUCH easier to use and read than the Adobe DTM Switch plugin which utilizes the Console.