2. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 OBJECTIVES After studying Chapter 10, the reader should be able to: 1.Prepare for ASE Electrical/Electronic Systems (A6) certification test content area “A” (General Electrical/Electronic Systems Diagnosis). 2.Explain the wire gauge number system. 3.Describe how fusible links and fuses protect circuits and wiring. 4.List the steps for performing a proper wire repair.

3. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 AUTOMOTIVE WIRING Most automotive wire is made from strands of copper covered by insulating plastic.

4. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 AUTOMOTIVE WIRING American Wire Gauge Wiring is sized and purchased according to gauge size as assigned by the American wire gauge (AWG) system. AWG numbers can be confusing because as the gauge number increases, the size of the conductor wire decreases. –Therefore, a 14 gauge wire is smaller than a 10 gauge wire.

5. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 AUTOMOTIVE WIRING American Wire Gauge

6. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 AUTOMOTIVE WIRING Metric Wire Gauge Most manufacturers indicate on the wiring diagrams the metric wire gauge sizes measured in square millimeters (mm2) of cross-sectional area.

7. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 AUTOMOTIVE WIRING Metric Wire Gauge

8. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 BRAIDED GROUND STRAPS All vehicles use ground straps between the engine and body and/or between the body and the negative terminal of the battery. Many of the engine-to- body straps are braided ground straps and are uninsulated. FIGURE 10-1 All lights and accessories ground to the body of the vehicle. Body ground wires such as this one are needed to conduct all of the current from these components back to the negative terminal of the battery. The body ground wire connects the body to the engine. Most battery negative cables attach to the engine.

9. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 BATTERY CABLES Battery cables are the largest wires used in the automotive electrical system. The cables are usually 4 gauge, 2 gauge, or 1 gauge wires (19 mm2 or larger). FIGURE 10-2 Battery cables are designed to carry the heavy starter current and are therefore usually 4 gauge or larger wire. Auxiliary wiring for accessories and other electrical components is also connected to the positive battery cable on this vehicle. The plastic conduit (also called split-loom tubing) reduces the risk of damage.

10. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 JUMPER CABLES Jumper cables are 4 to 2/0 gauge electrical cables with large clamps attached and are used to connect a vehicle that has a discharged battery to a vehicle that has a good battery.

11. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 FUSES AND CIRCUIT PROTECTION DEVICES Fuses should be used in every circuit to protect the wiring from overheating and damage caused by excessive current flow as a result of a short circuit or other malfunction. Many fuses are used to protect more than one circuit of the automobile.

12. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 FUSES AND CIRCUIT PROTECTION DEVICES FIGURE 10-3 A typical automotive fuse panel.

13. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 FUSES AND CIRCUIT PROTECTION DEVICES Blade Fuses The color of the plastic of blade fuses indicates the maximum current flow, measured in amperes.

14. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 FUSES AND CIRCUIT PROTECTION DEVICES Blade Fuses FIGURE 10-4 Blade-type fuses can be tested through openings in the plastic at the top of the fuse.

15. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 FUSES AND CIRCUIT PROTECTION DEVICES Mini Fuses To save space, many vehicles use mini (small) blade fuses. FIGURE 10-5 Three sizes of blade-type fuses: mini on the left, standard or ATO type in the center, and maxi on the right.

16. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 FUSES AND CIRCUIT PROTECTION DEVICES Maxi Fuses Maxi fuses are a large version of blade fuses and are used to replace fusible links in many vehicles.

17. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 FUSES AND CIRCUIT PROTECTION DEVICES Pacific Fuse Element First used in the late 1980s, Pacific fuse elements (also called a fuse link or auto link) are used to protect wiring from a direct short-to-ground. FIGURE 10-6 A comparison of the various types of protective devices used in most vehicles.

18. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 FUSES AND CIRCUIT PROTECTION DEVICES Testing Fuses It is important to test the condition of a fuse if the circuit being protected by the fuse does not operate. –Most blown fuses can be detected quickly because the center conductor is melted. FIGURE 10-7 To test a fuse, use a test light to check for power at the power side of the fuse. The ignition switch and lights may have to be on before some fuses receive power. If the fuse is good, the test light should light on both sides (power side and load side) of the fuse.

19. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 FUSES AND CIRCUIT PROTECTION DEVICES Circuit Breakers Circuit breakers are used to prevent harmful overload (excessive current flow) in a circuit by opening the circuit and stopping the current flow to prevent overheating and possible fire caused by hot wires or electrical components.

20. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 FUSES AND CIRCUIT PROTECTION DEVICES Circuit Breakers FIGURE 10-8 Typical blade circuit breaker fits into the same space as a blade fuse. If excessive current flows through the bimetallic strip, the strip bends and opens the contacts and stops current flow. When the circuit breaker cools, the contacts close again, completing the electrical circuit.

21. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 FUSES AND CIRCUIT PROTECTION DEVICES Circuit Breakers Examples are the circuits for the following accessories. –Power seats –Power door locks –Power windows FIGURE 10-9 These electrical symbols are used to represent circuit breakers.

22. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 FUSES AND CIRCUIT PROTECTION DEVICES PTC Circuit Protectors Positive temperature coefficient (PTC) circuit protectors are solid state (without moving parts). –Unlike circuit breakers or fuses, PTC circuit protection devices do not open the circuit, but provide a very high resistance between the protector and the component. FIGURE 10-10 (a) Normal operation of a PTC circuit protector in a power window motor circuit. Note the many conducting paths. With normal current flow, the temperature of the PTC circuit protector remains normal. (b) When current exceeds the amperage rating of the PTC circuit protector, the polymer material that makes up the electronic circuit protector increases in resistance. As shown here, a high-resistance electrical path still exists even though the motor will stop operating as a result of the very low current flow through the very high resistance. The circuit protector will not reset or cool down until voltage is removed from the circuit.

23. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 FUSES AND CIRCUIT PROTECTION DEVICES PTC Circuit Protectors The electronic control unit (computer) used in most vehicles today incorporates thermal overload protection devices. FIGURE 10-11 PTC circuit protectors are used extensively in the power distribution center of this Chrysler vehicle.

24. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 FUSES AND CIRCUIT PROTECTION DEVICES Fusible Links A fusible link is a type of fuse that consists of a short length of standard copper-strand wire covered with a special nonflammable insulation.

25. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 FUSES AND CIRCUIT PROTECTION DEVICES Fusible Links FIGURE 10-12 Fusible links are usually located close to the battery and are usually attached to a junction block. Notice that they are only 6 to 9 in. long and feed more than one fuse from each fusible link.

26. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 FUSES AND CIRCUIT PROTECTION DEVICES Fusible Links Fusible links are installed as close to the battery as possible so that they can protect the wiring and circuits coming directly from the battery.

27. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 FUSES AND CIRCUIT PROTECTION DEVICES Fusible Links FIGURE 10-13 (a) Demonstration showing the function of a fusible link by connecting a battery to each end with jumper cables. (b) After about 1 to 2 seconds, smoke starts to roll out from around the insulation. (c) After about 5 seconds, smoke fills the area as the wire inside finally melts and breaks (opens) the circuit. (d) The fusible link afterward.Notice that the special high-temperature insulation is unharmed even though the copper conductor has melted in half.

28. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 FUSES AND CIRCUIT PROTECTION DEVICES Checking Fusible Links Fusible links can melt and not show any external evidence of damage. To check a fusible link, gently pull on each end to see if it stretches. If the insulation stretches, then the wire inside has melted and the fusible link must be replaced after determining what caused the link to fail.

29. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 TERMINALS AND CONNECTORS A terminal is a metal fastener attached to the end of a wire, which makes the electrical connection. The term connector usually refers to the plastic portion that snaps or connects together, thereby making the mechanical connection.

30. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 TERMINALS AND CONNECTORS FIGURE 10-14 Some terminals have seals attached to help seal the electrical connections.

31. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 TERMINALS AND CONNECTORS FIGURE 10-15 Separate a connector by opening the lock and pulling the two apart. FIGURE 10-16 The secondary locks help retain the terminals in the connector.

32. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 TERMINALS AND CONNECTORS FIGURE 10-17 Use a small removal tool, sometimes called a pick, to release terminals from the connector.

33. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 WIRE REPAIR Solder Solder is an alloy of tin and lead used to make a good electrical contact between two wires or connections in an electrical circuit. FIGURE 10-18 Always use rosin-core solder for electrical or electronic soldering. Also, use small- diameter solder for small soldering irons. Use large- diameter solder only for large-diameter (large-gauge) wire and higher wattage soldering irons (guns).

34. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 WIRE REPAIR Solder Soldering a wiring splice includes the following steps. –While touching the soldering gun to the splice, apply solder to the junction of the gun and the wire. –The solder will start to flow. Do not move the soldering gun. –Just keep feeding more solder into the splice as it flows into and around the strands of the wire. –After the solder has flowed throughout the splice, remove the soldering gun from the splice and allow the solder to cool slowly.

35. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 WIRE REPAIR Crimping Terminals Terminals can be crimped to create a good electrical connection if the proper type of crimping tool is used.

36. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 WIRE REPAIR Crimping Terminals FIGURE 10-20 Notice that to create a good crimp the open part of the terminal is placed in the jaws of the crimping tool toward the anvil or the W-shape part. FIGURE 10-21 All hand-crimped slices or terminals should be soldered to be assured of a good electrical connection. Good fillets means that the solder should flow slightly from the clip and be smooth and shiny in appearance.

37. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 WIRE REPAIR Heat Shrink Tubing Heat shrink tubing is usually made from polyvinyl chloride (PVC) or polyolefin and shrinks to about half of its original diameter when heated; this is usually called a 2:1 shrink ratio. FIGURE 10-22 A butane torch especially designed for use on heat shrink applies heat without an open flame, which could cause damage.

38. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 WIRE REPAIR Crimp-and-Seal Connectors Crimp-and-seal connectors contain a sealant and shrink tubing in one piece and are not simply butt connectors. FIGURE 10-23 A typical crimp-and-seal connector. This type of connector is first lightly crimped to retain the ends of the wires and then it is heated. The tubing shrinks around the wire splice and a thermoplastic glue melts on the inside to provide an effective weather-resistant seal.

39. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 WIRE REPAIR Crimp-and-Seal Connectors The usual procedure specified for making a wire repair using a crimp-and-seal connector is as follows: –Strip the insulation from the ends of the wire (about 5/16 in. or 8 mm). –Select the proper size of crimp-and-seal connector for the gauge of wire being repaired. Insert the wires into the splice sleeve and crimp. –Apply heat to the connector until the sleeve shrinks down around the wire and a small amount of sealant is observed around the ends of the sleeve.

40. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 WIRE REPAIR Crimp-and-Seal Connectors FIGURE 10-24 The left side of this crimp-and-seal connector has been gently crimped and heated. Note how the connector has shrunk down around the wire. The heat has also released a thermal sealant that forms an effective environmental seal around the wire.

41. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 WIRE REPAIR Aluminum Wire Repair Many automobile manufacturers use plastic- coated solid aluminum wire for some body wiring. Because aluminum wire is brittle and can break as a result of vibration, it is only used where there is no possible movement of the wire, such as along the floor or sill area.

42. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 WIRE REPAIR Aluminum Wire Repair Step 1 Carefully strip only about 1/4 in. (6 mm) of insulation from the aluminum wire, being careful not to nick or damage the aluminum wire case. Step 2 Use a crimp connector to join two wires together. Do not solder an aluminum wire repair. Solder will not readily adhere to aluminum because the heat causes an oxide coating on the surface of the aluminum. Step 3 The spliced, crimped connection must be coated with petroleum jelly to prevent corrosion. Step 4 The coated connection should be covered with shrinkable plastic tubing or wrapped with electrical tape to seal out moisture.

43. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 SUMMARY 1.The higher the AWG size number, the smaller the wire. 2.Metric wire is sized in square millimeters (mm2) and the higher the number, the larger the wire. 3.All circuits should be protected by a fuse. The current in the circuit should be about 80% of the fuse rating. 4.Circuit breakers and fusible links are other circuit protection devices. 5.A terminal is the metal end of a wire, whereas a connector is the plastic housing for the terminal. 6.All wire repair should use either soldering or a crimp-andseal connector

44. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 REVIEW QUESTIONS 1.Describe the American wire gauge (AWG) system and compare it with the metric system. 2.Explain the difference between a wire and a cable. 3.Explain the difference between a terminal and a connector. 4.Discuss how fuses, PTC circuit protectors, circuit breakers, and fusible links protect a circuit. 5.Describe how to perform a wire repair.

45. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 CHAPTER QUIZ 1.The higher the AWG number, _____. a)The smaller the wire b)The larger the wire c)The thicker the insulation d)The more strands in the conductor core

46. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 CHAPTER QUIZ 2.Metric wire size is measured in units of _____. a)Meters b)Cubic centimeters c)Square millimeters d)Cubic millimeters

47. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 CHAPTER QUIZ 3.Which statement is true about fuse ratings? a)The fuse rating is measured in volts. b)The fuse rating should be higher than the normal current for the circuit. c)A replacement fuse rating should be the same as the original fuse. d)Both b and c are correct.

48. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 CHAPTER QUIZ 4.Which statements are true about wire, terminals, and connectors? a)Wire is called a lead, and the metal end is a connector. b)A connector is usually a plastic piece where terminals lock in. c)A lead and a terminal are the same thing. d)Both a and c are correct.

49. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 CHAPTER QUIZ 5.The type of solder that should be used for electrical work is _____. a)Rosin core b)Acid core c)60/40 with no flux d)50/50 with acid paste flux

50. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 CHAPTER QUIZ 6.A technician is performing a wire repair on a circuit that uses 18 gauge wire. The parts department does not have 18 gauge wire but it does have 16 gauge wire and 20 gauge wire. Technician A says to use the 16 gauge wire. Technician B says to use the 20 gauge wire. Which technician is correct? a)Technician A only b)Technician B only c)Both Technicians A and B d)Neither Technician A nor B

51. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 CHAPTER QUIZ 7.Two technicians are discussing fuse testing. Technician A says that a test light should light on both test points of the fuse if it is okay. Technician B says the fuse is defective if a test light only lights on one side of the fuse. Which technician is correct? a)Technician A only b)Technician B only c)Both Technicians A and B d)Neither Technician A nor B

52. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 CHAPTER QUIZ 8.If a wire repair, such as that made under the hood or under the vehicle, is exposed to the elements, which type of repair should be used? a)Wire nuts and electrical tape b)Solder and adhesive-lined heat shrink or crimp- and-seal connectors c)Butt connectors d)Rosin-core solder and electrical tape

53. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 CHAPTER QUIZ 9.Many ground straps are uninsulated and braided because _____. a)They are more flexible to allow movement of the engine without breaking the wire b)They are less expensive than conventional wire c)They help dampen radio-frequency interference (RFI) d)Both a and c are correct

54. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 CHAPTER QUIZ 10.What causes a fuse to blow? a)A decrease in circuit resistance b)An increase in the current flow through the circuit c)A sudden decrease in current flow through the circuit d)Both a and b

55. Automotive Electricity and Electronics, 2/e By James D Halderman © 2009 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 END