Also this model has spring contacts for the headlights; sometimes the contacts lose tension, resulting in headlights (or marker lights) that do not illuminate. This is a common issue with MTH models but has a very easy fix. Remove the shell, locate the spring contacts (usually clipped to one of the shell screw studs) and gently pull the spring contacts to move the contact closer to the bottom of the shell. Reinstall the shell and see if the lights come on. If the lights do not come on try pressing down on the shell to make the springs temporarily make contact; if the lights come on pull the spring contacts out further to compensate and reinstall the shell.
-John