© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Publisher The Goodheart-Willcox Co., Inc. Tinley Park, Illinois by Russell Krick

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Headlamp System  Components:  battery  headlamp wiring  fuse panel  light switch  dimmer switch  headlamps, taillights, marker lights, and instrument lights

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Headlamp Switch Controls current to the headlamp system

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only  Controls several circuits  headlights (high and low beams)  flash-to-pass (energizes high beams)  turn signals  cruise control  windshield wipers Multifunction Switch

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Headlamp Dimmer Switch Controls high and low beam function

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only  Components:  fuse  horn switch  horn  wiring  When the horn switch is closed, it activates the horn relay  The relay carries high current

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Horn  Contains a coil, points, and a flexible diaphragm  Coil and point action makes the plunger slide in and out of the coil, moving the diaphragm

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Short Circuit  A current-carrying wire is touching another wire or ground  May cause a blown fuse, a burned fusible link, or an open circuit breaker  A short to another wire may cause the wrong system to operate

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Open Circuit  Prevents systems from working  Caused by a broken wire, a disconnected electrical connection, or a bad switch  To test, use a test light or voltmeter  Check for power at the supply (fuse), moving toward the component (load) if power is found

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Using Wiring Diagrams  Diagrams show the relationship of wires and components  Information available:  wire color coding  component location  splices and connections  symbols  component drawings

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Relay Relays are a common source of trouble in all types of circuits