Deck 16: General Electrical System Diagnostics and Service

Question 1

Technician A says fuses and other circuit protection devices normally wear out. Technician B says to avoid future problems, replace a bad fuse with a higher ampere-rated fuse. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Answer 1

D

Question 2

All types of circuit protection devices can be checked with an ohmmeter or test light.

Answer 2

True

Question 3

If rosin core solder is not available, acid core solder can be used as a substitute.

Answer 3

False

Question 4

Connecting an ohmmeter to a live circuit usually results in damage to the meter.

Question 5

High resistance in a circuit causes decreased current flow.

Question 6

When using a DMM to test resistance, the red lead is connected to the A jack.

Question 7

A circuit is open when it is complete.

Question 8

While discussing how to test a switch, Technician A says the action of the switch can be monitored by a voltmeter. Technician B says the continuity through the switch can be checked by measuring the resistance across the switch terminals using an ohmmeter. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 9

Electrical symbols are standardized throughout the automotive industry.

Question 10

Connecting an ohmmeter into a live circuit can damage the meter.

Question 11

Technician A says electrical circuit resistance causes voltage drop. Technician B says high-resistance problems cause an increase in current flow. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 12

A voltage drop test can find excessive resistance in a circuit that may not be detected using an ohmmeter.

Question 13

When a circuit protection device (fuse, circuit breaker)opens due to higher than normal current, a short is the likely cause.

Question 14

The schematic for a relay is typically shown on the outside of the relay.

Question 15

An ohmmeter can be used to check for continuity.

Question 16

Analog meters should not be used to test electronic components.

Question 17

A switch that is in the closed position should not have more than 300 millivolts voltage drop between input and output terminals.

Question 18

An analog oscilloscope can freeze a captured signal for close analysis.

Question 19

A wiring diagram shows the actual position of parts on a vehicle.

Question 20

The black DMM test lead always plugs into the COM input jack.

Question 21

When connecting a conventional ammeter to a circuit, _____.

A)the circuit must turned on
B)the ammeter must be wired in series with the circuit
C)the anticipated load current must be less than the ammeter's maximum current rating
D)All the answers are correct.

Question 22

Resistance checks are being discussed. Technician A says the component must be disconnected from the system before checking. Technician B says an infinite reading means the component is shorted. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 23

A technician is checking a circuit with excessive resistance. The current flow through the circuit should be 10 amps, but a check with an ammeter measures only 6 amps. The technician measures a voltage drop of 1.0 volts across the switch terminals when the circuit is turned on. What is the resistance of the switch?

A)1/60 ohm
B)1/6 ohm
C)6 ohms
D)60 ohms

Question 24

A technician is testing a connector in a circuit with a voltmeter. With the power on in the circuit, the meter reads 12 volts when the leads are placed on each side of the connector. This indicates that the connector _____.

A)is shorted to ground
B)is open
C)is good
D)has current flowing through it

Question 25

Voltage drop testing is being discussed. Technician A connects the red voltmeter lead to the most positive side of the circuit being tested and the black lead to the most negative side or part of the circuit being tested. Technician B says the test must be conducted with the circuit operating with normal amounts of current. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 26

The wave form of constant DC voltage on a lab scope is a _____.

A)square wave
B)sawtooth wave
C)sine wave
D)flat line

Question 27

When testing the high-voltage circuits on a hybrid vehicle, a _____type meter and test leads must be used.

A)Cat II
B)Cat III
C)Cat IV
D)Cat V

Question 28

Oscilloscopes are being discussed. Technician A says the vertical positions represent time. Technician B says the horizontal positions represent voltage. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 29

DMMs that can measure temperature use a _____ adapter that is placed on or near the object to be checked.

A)thermometer
B)thermocouple
C)manometer
D)refractometer

Question 30

Sensor problems are being discussed. Technician A says small amounts of unwanted resistance in a low voltage sensor circuit will not have a significant effect on the vehicle's performance. Technician B says a poor ground in the reference voltage circuit can cause higher than normal readings at the computer. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 31

Technician A says a circuit breaker can be reset after the problem that tripped the circuit breaker is fixed by disconnecting the power to the circuit breaker for a few seconds. Technician B says the circuit breaker can be reset by pressing the reset button on the breaker. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 32

When using an inductive current probe adapter on a DMM, _____.

A)the DMM is set for DC amps
B)the arrow on the clamp faces toward the battery [source voltage]
C)the thumb wheel on the probe is adjusted to zero on the DMM
D)All the answers are correct.

Question 33

When testing resistance in a circuit with an ohmmeter, _____.

A)the ohmmeter is connected in parallel to the circuit and the circuit is turned on
B)the ohmmeter is connected in series to the circuit and the circuit is turned on
C)the circuit or component must first be disconnected from the power source, then the ohmmeter is connected in parallel with the component being tested
D)the circuit or component must first be disconnected from the power source, then the ohmmeter is connected in series with the component being tested

Question 34

All the following are lab scope adjustments EXCEPT:

A)trigger level
B)slope
C)trigger source
D)amperage level

Question 35

The waveform of AC voltage is typically a _____.

A)square wave
B)sawtooth wave
C)sine wave
D)flat line

Question 36

Technician A says uses an ohmmeter to measure resistance of a component. Technician B uses a voltmeter to measure voltage drop. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 37

Technician A uses a voltmeter to check circuit resistance. Technician B uses an ohmmeter to check circuit resistance. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 38

Technician A uses a splice clip while soldering two wires together. Technician B twists the wire strands of the wire ends together before soldering. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 39

What is the best tool to use to find the cause of an intermittent problem in a low-voltage DC circuit?

A)graphing multimeter (GMM)
B)digital storage oscilloscope
C)digital voltmeter
D)test light

Question 40

When setting up a lab scope to measure a waveform that ranges from 0 to 15 volts; if there are eight vertical divisions, what must the voltage level be set at to display the entire waveform?

A)100 millivolts
B)500 millivolts
C)1 volt
D)2 volts

Question 41

A conventional ammeter is always connected in ____________________ with the circuit.

Question 42

The number of cycles per second is called ____________________.

Question 43

Technician A uses heat shrink tubing to insulate and seal soldered wire connections. Technician B wraps the soldered connection with electrical tape. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 44

A voltmeter is connected in ____________________ with the circuit.

Question 45

A beeping noise coming from the DMM when the function selector is set to ohms indicates that the circuit has ____________________.

Question 46

Technician A uses the schematic diagram to locate exactly where on the vehicle all of the circuit components are located. Technician B uses the electrical schematic diagram to trace the flow of current through all the switches, wires, connectors, circuit protection devices, and grounds related to the problem before he begins testing. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 47

Taking electrical measurements from the external wire terminal ends on the outside of a plugged-in electrical connector is called ____________________.

Question 48

Technician A says dielectric grease is used on wire terminals and connectors to prevent corrosion. Technician B says dielectric grease reduces the resistance between the terminals. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 49

You are wiring a vehicle for a trailer hitch. The trailer will have eight parking lamps. Each parking lamp uses a 6 watt light bulb. What size fuse should be used to supply power for the parking lamp circuit? (Assume that the normal operating voltage is 14 volts.)

Question 50

The most common way to check a variable resistor is with a(n)____________________.

Question 51

The wiring harness for the SRS (air bag)circuit has a _____ harness cover.

A)red
B)blue
C)day glow green
D)yellow

Question 52

A technician tests a circuit that uses a ground-controlled relay to provide power to the circuit load. With the relay installed in its socket, the control terminal of the relay is grounded by a jumper wire; nothing happens. Technician A checks the coil input terminal for voltage. Technician B connects a jumper wire between battery negative and the output terminal of the relay to check if the load is the problem. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 53

Which piece of information about the vehicle's wiring cannot be found in the electrical schematics?

A)wire color
B)wire size
C)connector terminal designation
D)component location on vehicle

Question 54

A voltage drop test is performed to find unwanted ____________________.

Question 55

An electrical ____________________ is a diagram used to troubleshoot a circuit.

Question 56

____________________ solder is used to repair electrical wiring.

Question 57

Duty cycle is measured in ____________________.

Question 58

The best method for testing wires and electrical connections is a(n)_____.

A)ohmmeter test
B)voltage drop test
C)inductive ammeter
D)infrared pyrometer

Question 59

A technician is diagnosing the cause of an insufficient heat problem. He/She notices the fan is working but not providing much air flow. He/She disconnects the fan power feed wire and connects the fan to the battery using a fused jumper wire. The specification for the fan motor is 16 amps. His/Her ammeter shows 26 amps when the fan is jumped directly to the battery. What could be the problem?

A)bad fan motor ground
B)high resistance in the fan motor wiring
C)shorted wiring in the fan motor
D)All the answers are correct.

Question 60

A potentiometer [type of variable resistor] can be tested with all the following tools EXCEPT:

A)test light
B)voltmeter
C)ohmmeter
D)digital lab scope (DSO)

Question 61

What units of measurement are used to measure frequency?____________________

Question 62

What are the five steps in diagnosing an electrical problem?

Question 63

The most common cause of high resistance in electrical wiring is ____________________.

Question 64

What does the scope's trigger do?

Question 65

How does an inductive amps probe measure current without touching any wires in the circuit?

Question 66

What are three ways to check a fuse?

Question 67

What is a short circuit?

Question 68

The radiator fan on a vehicle is working, but it is turning at a much slower speed than normal. The specifications for the fan motor are 25 amperes. Your DMM has a maximum amperage of 10 amps. What should you do to test the fan motor current?

Question 69

Other than measure voltage, current and resistance most DMMs (DVOMs)can also measure and test what other factors?

Question 70

What are the three classifications of electrical problems?

Question 71

Explain how you would bench test a relay (the relay is removed from the vehicle).

Question 72

What are the four major parts (areas)of a digital multimeter?

Question 73

When using an inductive amps probe adapter on a DMM, the function selector should be set to ____________________.

Question 74

How can you test a circuit that blows its fuse as soon as it is in inserted into the fuse holder?