Cigarette lighter

This lighter is a pretty simle system. Looks like there is a 15a fuse that supplies power, and it runs to s common ground. If this is the only thing that is not working, then it is probably not the ground. Looks like one or more of the funtions of your clock are powered by the same fuse, so if you clock is working normally, it might just be the lighter itself. I would try and get to the back of the lighter, and check the plug and make sure it is plugged in good. Find someone who has a volt/ohm meter, and check for power on pin 2 and a ground on pin 1. If you have both, then replace the lighter.
If you dont have a ground, then follow the ground wire and see where you loose the ground. If you have no power, check for power at the 15a CIG fuse. Track down the wire between the fuse and lighter to find the break. Could just be a bad lighter.
Have you tried both the lighter and a charger plug?

Thanks for the info. I am sure that info will help others if they have a similar issue.