Look at the element. That coil at the working end of the lighter. Is it broken? Is the center still sticking out? The most common reason for the lighter to quit is it is open. The element can be replaced. It will unscrew from the knob. new ones are easy to get from FLAPS and vendors. Crud at the bottom of the socket can also keep it from getting a good connection. Real simple thing and not too hard to work on. If the coil is broken it will have to be replaced.
