This study was designed to examine the feasibility of using simulation as a means of teaching vocational-technical students to detect and identify malfunctions in selected electrical and mechanical systems. A dynamic simulator was employed which features interchangeable panels and logic that permits the simulation of electrical or mechanical systems in automobiles, heating and air conditioning systems, and various appliances. The study involved 205 automotive mechanics enrollees at four Pennsylvania area vocational-technical schools. The treatment group received individual, self-paced instruction on the simulator and performed significantly better than the non-treatment group which did not receive any simulator instruction. Affective, cognitive, and experience type variables were predictive of troubleshooting efficiency, while cognitive and experience variables predicted success in troubleshooting proficiency. Instructors felt that the simulators motivated students, facilitated instruction, and enhanced learning. (Author/GEB)