This module is one of a series of teaching guides that cover diesel mechanics. The module contains eight instructional units that cover the following topics: (1) introduction to electrical systems; (2) electrical circuits; (3) electrical indicator circuits; (4) storage batteries; (5) starting systems and circuits; (6) ignition circuits; (7) alternator charging circuits; and (8) emergency shut-down circuits. Each instructional unit follows a standard format that includes some or all of these eight basic components: performance objectives, suggested activities for teachers and students, information sheets, assignment sheets, job sheets, visual aids, tests, and answers to tests and assignment sheets. All of the unit components focus on measurable and observable learning outcomes and are designed for use for more than one lesson or class period. Instructional task analyses; a list of tools, equipment, and materials; and 14 references are also included. (KC)