Anyone whose car or light truck has broken down knows the importance of the service technician’s job. Continued advancements in technology have created and redefined the role of the automotive technician. Although hand skills remain important, physical work is no longer the major aspect of automotive servicing. Today, the emphasis is on diagnostics, a process that requires an ability to think through problems in the abstract. The ability to diagnose the source of the problem quickly and accurately, one of the mechanic’s most valuable skills, requires good reasoning ability and a thorough knowledge of automobiles. In fact, many mechanics consider diagnosing “hard to find” troubles one of their most challenging and satisfying duties.