ASE Practice Test (A6: Electrical/Electronic Systems)
To check the continuity of wires that carry digital signals, which of the following tools can be used?
Correct answer: Logic probe
A logic probe is the only device that measures digital signals.
When using the passenger side control switch, the passenger side power window works properly, but when using the driver's side master control switch, the window only works in the DOWN position. Which of these possibly be the source of the problem?
Correct answer: An open circuit in the driver’s side master control switch
The cause could be an open circuit in the driver’s side master control switch.
Which of the following statements regarding a series circuit is correct?
Correct answer: Highest resistance contains the highest voltage drop
According to Kirchhoff’s Voltage Law: Voltage higher before resistance than after, which is the result of total applied voltage not equal at both ends of a single load circuit. The resistance opposes electron flow which results in voltage loss applied to the load. This loss is voltage drop with the voltage consumed as current travels through resistance. If you have higher resistance, you have higher drop.
A fully charged 12 volt battery should indicate how much voltage on the open circuit voltage (OCV) test when using a DMM (Digital Multimeter).
Correct answer: 12.6 volts
The standard is 2.1 volts per cell and 2.1 times 6 is 12.6 volts.
Technician X says that if a fusible link in the alternator charging circuit is replaced with system sized wire, the circuit will be unprotected. Technician Y says that if a fusible link in the alternator charging circuit is replaced with system sized wire, the battery will overcharge. Who is right?
Correct answer: X only
Technician X is correct. The circuit will be unprotected if a fusible link in the alternator charging circuit is replaced with system sized wire.
When using a DMM voltmeter function to evaluate voltage drop, how should the meter leads be connected?
Correct answer: Across the circuit or component
You want to connect your meter leads across the circuit or component. Voltage always gets checked across the circuit or in parallel. The other answers aren’t the appropriate way to connect meter leads in this situation.
Two technicians are discussing a battery's state of charge. Technician X says a specific gravity of 1.225 at 80F indicates that a battery's state of charge is approximately 75%. Technician Y says you can use a hydrometer to check battery state of charge on a maintenance free battery. Who is right?
Correct answer: X only
Technician X is correct and Technician Y is wrong because maintenance free batteries do not have openings to check the specific gravity of the electrolyte with a hydrometer.
A starter solenoid clicks but the starter does not crank the engine. Technician X says that burned solenoid contacts could be the cause. Technician Y says that a poor battery cable connection could be the cause. Who is right?
Correct answer: Both X and Y
Both technicians are correct.
When linked to both sides of the rotor, an analog ohmmeter needle will not move. What does the rotor winding indicate?
Correct answer: It is open
This ohmmeter is showing infinite resistance or infinity. This is what happens when the needle doesn’t move. With the rotor winding shows, the circuit is open.
When a technician performs a load test on a battery, the battery voltage falls below specifications. Which of the following actions is the MOST LIKELY to be taken?
Correct answer: Replace the battery
The battery was tested under load and failed.
The following could cause high starter current draw, EXCEPT:
Correct answer: a failed starter relay
A failed starter relay could not be the cause of high starter current draw.
Technician X states that a short circuit to ground in a circuit decreases resistance. Technician Y states that a short circuit increases current flow. Who is correct?
Correct answer: Both technicians
Both technicians are correct. There’s little or no resistance with a short to ground. It’s also true that the current flow increases when resistance decreases.
Two technicians are discussing testing a battery using an electronic conductance or continuity tester. Technician X says some of these testers can load test a battery. Technician Y says you need to make sure that the ignition switch and all accessories are off. Who is right?
Correct answer: Y only
Technician X is wrong because this device cannot apply a load. It checks battery conductance.
On an automatic transmission vehicle, the starter does not crank and the solenoid does not click. Any of these could be the source of the problem. EXCEPT
Correct answer: an open solenoid hold-in winding
An open solenoid hold-in winding could not be the cause of the problem.
You discover the current draw is higher than specified while performing a starter current draw test. The battery voltages and cranking speed appear to be lower than the manufacturer's specifications. What's the source of your issue?
Correct answer: Worn bushings in the starter motor
As the motor turns slower, it draws more amperage. Worn bushings cause the motor to turn slower than it should. This leads to a high current draw.
Two technicians are discussing an alternator with zero output. Technician X says the field circuit may have an open circuit. Technician Y says the fusible link may be open from the battery to the alternator. Who is right?
Correct answer: Both X and Y
Both statements are correct.
The oil pressure light stays on whenever the engine is running. The oil pressure has been checked and is at specification. Technician X says that a ground in the circuit between the indicator light and the pressure switch could be the cause. Technician Y says that an open in the pressure switch could be the cause. Who is right?
Correct answer: X only
Technician X is correct. A ground in the circuit between the indicator light and the pressure switch could be the cause why the oil pressure light stays on whenever the engine is running.
Technician X states that a loose serpentine alternative drive belt might lead to overcharging. Technician Y states that undersized wiring between the battery and alternator might cause undercharging. Who is correct?
Correct answer: Technician Y
Tech X is incorrect because undercharging is the result of a slipping belt. Tech Y is right because the undersize wiring leads to undercharging. This is caused by higher resistance.
A low-output alternator is being full-fielded to determine the cause. Which of the following is the LEAST likely result of full-fielding the alternator?
Correct answer: Low battery voltage level
Full fielding removes the regulator from controlling field current allowing the alternator to go to full output and is unlikely to produce a low battery voltage. This action normally produces high current and voltage. P (Power) = I (Current) x E (Voltage) and is least likely to occur.
With the engine running and based in the charging system shown. What will be the digital multimeter (DMM) will display?
Correct answer: charging circuit voltage drop
In the charging system shown, the digital multimeter (DMM) will display the charging circuit voltage drop.
Out of these options, what is the least likely cause of a dim headlight?
Correct answer: Low output from the alternator
All of these reasons could be the cause of a dim headlight but D is the least likely. More common symptoms of a failing alternator are a dead battery, engine stalling, odd noises and the service engine light.
Technician X says high-intensity discharge (HID) headlights are generally brighter and have a blue tint. Technician Y says a defective turn signal bulb on one side can cause the turn signal on that side not to blink. Who is right?
Correct answer: Both X and Y
Both statements are correct.
In the circuit shown, the bulb does not light. To determine the actual voltage at the bulb, the technician should touch the positive probe of the voltmeter to:
Correct answer: point X and the negative probe to ground
To find the actual voltage at the bulb, the technician should touch the positive probe of the voltmeter to point X and the negative probe to ground.
The vehicle turn signals begin to flash too slow. Technician X believes that the issue is caused by a faulty flasher. Technician Y believes the bulb is an incorrect type. Who is correct?
Correct answer: Both technicians
Both techs are correct. The incorrect wattage and improperly rated flasher could cause the signal to flash incorrectly. Turn on the signal and inspect it to determine the problem.
Technician X says you aim HID (High Intensity Discharge) headlights on a level floor with an unloaded vehicle. Technician Y says when aiming any headlights, you must follow the state inspection specifications. Who is right?
Correct answer: Both X and Y
Both statements are correct.
The horns in the circuit shown operate only when a jumper wire is connected between terminals 30 and 87 of the horn relay. Technician X says that a failed horn relay could be the cause. Technician Y says that a short-to-ground in the circuit between the horn relay and the horn switch could be the cause. Who is right?
Correct answer: X only
Technician X is right. As shown in the circuit, a failed horn relay could be the cause.
For instrument panel wiring repairs, what solder type is needed?
Correct answer: Rosin core
Rosin core is the only solder type to ensure integrity in this repair. It’s specified for use on any electric repair. The other options would be unacceptable ways to perform the repair.
Technician X says an aiming screen will work on any headlight design to aim the headlights. Technician Y says mechanical aimers are used on HID (High Intensity Discharge) headlights. Who is right?
Correct answer: X only
Technician X is correct because the aiming screen is the tool of choice due to the many different headlight designs used. Technician Y is wrong because mechanical aimers are no longer used and were never used on HID headlights.
What is the most likely reason of a faulty fuel gauge indicating a full tank?
Correct answer: Wire leading to sending unit ground
While there could be many causes; this is the most likely as the question indicated. It can also cause other symptoms such as erratic readings and stuck on empty as well. The least common cause would be trouble with the instrument panel itself.
A wire to the sending unit being grounded is the most likely cause on most systems.
In instrument lighting, which of the following describes the MOST common type of electrical wiring used?
Correct answer: Copper stranded type
Copper stranded type electrical wiring is the correct answer because the other types are not common.