Chapter 21 POWERPOINT

Use the textbook to define these Technical Terms:

1. battery cables

2. chassis ground

3. connector diagram

4. dielectric grease

5. harness connector

6. heat shrink tubing

7. junction block

8. secondary resistance wire

9. shielded twisted pair wire

10. wiring harness

11. wiring schematic (also called wiring diagram)

Use the textbook to answer these discussion questions:

1. Explain the proper techniques to cut and strip wires.

Read the chapter summary below:

Summary

■ Most automotive circuits use stranded wire because it withstands vibration and movement better than solid wire.

■ Wire size is commonly given as a gage number. A smaller gage number represents a larger diameter conductor, and vice versa.

■ Wire resistance depends on the diameter of the conductor, wire length, the type of conductor, and temperature.

■ Wire color codes allow you to trace wire from one location to the next, even when some of the wire is hidden from view.

■ A wiring harness is a set of several wires enclosed in tape or a plastic protection device. Connectors branch out from the harness and link to electric components or other harness connectors.

■ Use wire stripping pliers to remove insulation from wires. Avoid using cutters to strip wires.

■ Soldering is the best way to join one wire to an- other or to join a wire to a terminal.

■ Electrical tape is commonly used to cover a metal joint after soldering. Liquid electrical tape is useful when the joint must be protected from moisture. Heat shrink tubing also covers and protects a soldered joint.

■ Crimp connectors provide a quick and easy method of joining wires or terminals to wires. Crimping pliers are used to form the metal part of the connector around the wire conductor. When possible, you should solder crimp connectors to ensure a permanent electrical connection.

■ Factory connectors usually have a locking feature that keeps the connectors from pulling apart with vibration. Use the correct procedure to release a connector without damage.

■ When replacing a fuse link, use the correct replacement wire gage size. Always solder the new link in place to prevent unwanted resistance.

■ Wiring diagrams show how wires connect to electric/electronic components.

■ Wire splices are usually shown with a dot where the two wires connect.

■ A remote ground has an extra wire running to ground. A chassis ground uses the metal part of the component to serve as the ground.

■ An alternate circuit is a possible circuit variation. An optional circuit is one that is shown on the diagram but may not be in use.

■ Connector diagrams show connector locations and detail the terminals inside the connector.

■ A power distribution diagram shows how battery current is fed to major components.

■ A location grid can help you find the location of components or connections quickly on a large wiring diagram.

■ A main wiring diagram shows all electric components and wires. A system diagram only shows part of the main diagram. A block diagram uses blocks and symbols to represent components and is used for visualizing system operation.