AVR/Electrical System Test

Modern cars are highly reliant on electrical systems to function properly. The alternator, battery, and other electrical and electronic systems control much of the functionality of your car – and if they begin to fail, you may experience a wide variety of issues with your car.

Your vehicle’s electrical system consists of an alternator, starter, and battery. Your car battery is what gives the juice to the starter. The alternator, on the other hand, gives your battery the energy it needs to power your car consistently. Therefore, if any of the electrical components of your vehicles fail to work properly, you won’t be able to start your vehicle, or rather, your car won’t perform as desired, including power windows, door locks, lights, etc.

However, it can be easy to misdiagnose electrical problems with your vehicle. It helps to be proactive and have an AVR Test once or twice a year during your regular oil change. AVR stands for “alternator voltage regulator. With the right equipment, a tech can apply a measured electrical load to the battery and monitor the results. He or she can also display the output of the alternator and the amount of power the starter draws when engaged to find any potential system weaknesses.

Main Components

The Battery

Car batteries are responsible for the entire electrical current running your vehicle—the current to the ignition as well as the fuel system. Your fuel system is responsible for creating the combustion necessary for your engine to function.

Changing your battery every 5 years before you have problems will significantly decrease your risk of a breakdown, too.

The Alternator

As the engine is running, the alternator keeps the battery charged, and your electrical system powered. It is possible to start your car with a faulty alternator. However, it won’t be able to run for an extended period. In case your car’s alternator is faulty, your vehicle’s performance will be erratic. Due to a lack of power, the battery will discharge, and as a result, the engine will lose power. Scheduling a complete electrical system repair service with your local mechanic will tell you whether your alternator is generating the proper amount of voltage and current. This way, you are aware of the problem before the alternator finally fails.T

The Starter

The car battery is responsible for supplying power to start up your engine; the starter, on the other hand, gets the engine turning. Your car battery supplies a small amount of power to the starter motor. The starter, in turn, rotates the flywheel, turning the crankshaft triggering engine piston movement. It is due to this complex process that it is important to ensure that your starter works.

The Engine Won’t Crank Properly

The engine requires electrical power to start. Through the ignition switch, the battery has to provide the spark through a spark plug that ignites the fuel in your engine. If your engine won’t crank properly, this could be a sign of a bad battery, alternator, or another unrelated electrical problem.

The alternator of the car must work well with your battery to charge the vehicle’s electrical system. A bad alternator surely affects your car in many ways.

The most common issue you’ll have is “clicking” when you turn the key and attempt to start our car. This means that there is not enough current flow in the system to engage the engine. Usually, this is caused by a discharged or bad battery, but your starter could also be the source of the issue.

The starter motor should turn the engine over during ignition and allow everything else to happen. The starter motor allows the engine to suck air when the ignition is turned on.

If you hear a “grinding” noise during cranking, this could be because of a bad starter, or a faulty flywheel ring gear. If your car is older and has high mileage, there is a good chance that there is a fault in an electrical system. If these cases are persisting, then an electrical diagnosis is highly recommended. Scheduled maintenance is also advised to make your car stay in good condition.

You’re Experiencing Battery Problems

If you are having issues with your battery, don’t just replace it without checking the car’s electrical systems. Most car batteries last about 5 years – less in hot climates – so a dead battery or a faulty battery could be a problem.

However, the issue could also lie with your alternator, or somewhere else in the auto electrical system of your vehicle.

If you think your battery is at fault, start by checking your battery cables for corrosion, and ensure they’re fitted properly because they mainly power the car’s electronic systems. If your car still doesn’t start, you can consider taking your battery into an auto shop to see if it is functioning properly.

If your battery is in good condition and is confirmed to be working properly, your issue likely lies elsewhere. Diagnosing your car's electrical system is recommended so you can take your car to your nearest service station to have the alternator and other power systems checked. Electrical repair specialists provide strategy-based solutions to these problems. Car owners need to also understand the car’s charging system which keeps the electrical energy of the car running.

If you don’t know how to do diagnostic and repair, get a jumpstart, and get a professional technician to check your vehicle’s electrical system and do the tedious auto electric repair.

Headlights And Other Lights Are Not Working Properly

Your car’s lights are one of the most important things that your electrical system controls. Turn signals, brake lights, and headlights keep you safe on the road, and interior illumination and lamps ensure that you can see what you need to in dark conditions.

If your car’s electrical system is malfunctioning, you may notice that various lights start to dim. Dimming lights indicate charging malfunctions and low system voltage. The culprit could be a dying battery, loose wires, or a malfunctioning alternator belt.

If the check engine light of your dashboard lights it means that there is a minor or major issue with your car that needs auto electric repair. Check engine light is a malfunction indicator lamp that is signaled by the car’s engine computer saying that there is something wrong.

Corrosion of electrical systems may also be an issue. Unless you have a voltmeter handy (and know how to use it) you probably won’t be able to do electric diagnoses job yourself. If your car won’t start, it certainly has a car electrical issue, so take your car to a mechanic for full vehicle inspections.

CCA or Cold Cranking Amps

Cold Cranking Amps (CCA) is a rating used in the battery industry to define a battery’s ability to crank an engine in cold temperatures. 

It measures how much current (measured in Amps) a new, fully charged 12V battery could deliver for 30 seconds while maintaining 7.2V at  0°F (-18°C)

It’s harder to crank an engine in cold environments compared to a warm one. Cold temperature influences the engine and battery fluids. When cold, engine fluids increase in viscosity (thickness or density), making it harder to start.

It’s also harder to crank older engines as internal friction increases with age and mileage.

The cranking power an automotive battery requires to start an engine varies. It’s driven by several factors, including the engine size, temperature, and engine oil viscosity. 

For example, a 4-cylinder engine may not require as much cranking power as a larger 8-cylinder engine. The vehicle manufacturer takes all these factors into account when they spec out the original equipment (OE) car battery. Generally, the rule of thumb is 1 Cold Cranking Amp for every cubic inch of engine displacement (2 CCA for diesel engines). 


Jumping your own vehicle can cause damage to the car if not done correctly. Vehicles today are built with more electronics inside than ever before. Improperly jumping your car can cause harm to these electronics. Placing the clamps on the wrong terminals can short circuit or even damage parts beyond repair. It is possible to damage an alternator during a jump start and even after a jump start. The voltage regulator is solid state so any voltage spike from the final connection spark can fry it.

Batteries emit hydrogen gas and there is a chance that in the presence of a spark or flame they will ignite. "They can literally explode. The acid inside is highly corrosive for your eyes, skin, and clothes.


AVR Test once or twice a year during your regular oil change. It stands for “alternator voltage regulator. With the right equipment, a tech can apply a measured electrical load to the battery and monitor the results. He or she can also display the output of the alternator and the amount of power the starter draws when engaged.

Changing your battery every 5 years before you have problems will significantly decrease your risk of a breakdown.

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