Bad Voltage Regulator Symptoms

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What are bad voltage regulator symptoms? Frequently dead battery, dim headlights, check engine light illumination A bad voltage regulator will cause the battery to not charge and the headlights to always dim and may also trigger the check engine light to appear on the dashboard. A voltage regulator is installed in cars to monitor and regulate electric supply to specific electrical components of the car.

This voltage-regulating device works with the alternator to keep your car’s battery charged; the car’s battery, in turn, powers the electrical components of the vehicle, which includes the dashboard lights, power accessories, infotainment, and many others. Understanding the signs a bad voltage regulator would put up will let you fix the issue right in time.

Functions of the Voltage Regulator

bad voltage regulator symptoms
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We all know the alternator is the main component that charges the battery, but not many people know how it gets its electrical current. The voltage regulator is what feeds the alternator. The voltage regulator is in charge of keeping the right supply of power to the alternator – that’s its primary function.

So, if the voltage regulator is bad, the alternator will not get enough power to charge the battery, which means the car’s battery won’t get to supply the car’s electrical systems and devices with enough power to function.

In other words, the voltage regulator is the chief electrical component of a vehicle; when it gets bad, every other electrical component of the car will malfunction.

Bad Voltage Regulator Symptoms

1. Battery Issues

If your car’s battery constantly runs down and you’re certain it is not the alternator, or the battery itself is causing the problem, then the possible cause of the issue is a bad voltage regulator. The first signs of a bad voltage regulator are battery issues – your car’s battery would start malfunctioning like it had never before.

Even if you decide to put in a new battery, the issues will persist. A bad regulator will not let the battery charge fully because the alternator is not getting enough current as needed to power the 12- or 24-volt battery on your car.

When you are faced with a situation like this, it is best to troubleshoot the car using an OBDII tool to find the exact cause of the issue – whether it is the battery, alternator, or voltage regulator. Also, it is important to note that a faulty voltage regular could damage a good car battery by supplying higher or lower power to the alternator. This should be taken seriously.

2. Check Engine Light

Virtually any problem with your car’s engine will throw up the check engine light. So, seeing the check engine light come on doesn’t immediately tell what’s actually wrong with the car. However, if you had worked on the alternator recently (before the check engine light came on), it could hint that the voltage regulator is about to fail.

Notwithstanding, the best way to find the exact reason why the check engine light came on is by troubleshooting the car computer, then following the detected error codes to fix the errors with the engine parts. A bad voltage regulator will throw a P0562 or P0560 DTC – so if you got these codes on your OBDII scanner, the voltage regulator is bad.

3. High or Low Voltage Power Supply

As hinted quite severally in this article, the voltage regulator plays a crucial role in determining the amount of power supply to the alternator in a car. So, apparently, a faulty one can cause the regulator to trigger a higher or lower voltage supply to the alternator, which is not good for your car’s electrical components.

4. Dim Headlights

Electrical faults with a car can cause dim headlights – the situation whereby the headlights do not shine as bright as supposed, and it’s not like the headlight bulbs have burned out. Dim headlights are caused when the car’s battery does not supply sufficient electrical voltage to the headlights, which is most likely a result of low voltage supply from the regulator.

Related problems to this include flickering headlights and high beams not working. When you notice these signs, one of the first places to check is the voltage regulator. Apparently, you wouldn’t love to drive with dim or flickering headlights, especially if you drive at night – it’s dangerous, and allowing such situations to linger can damage the headlight bulbs over time.

5. Dashboard Lights Not Working

The instrument cluster dashboard and its icons need an electronic current to appear and notify you of whatever issue is wrong with the car or tell the driving mode you’re currently in. Without the right voltage supply, the dashboard light(s) won’t come on – even if it does, it may not be so bright for you to see the notifications/icons clearly because the voltage supply is low.

Notwithstanding, your car’s dashboard lights not coming on can possibly be due to other electrical faults, including a weak/dead car battery, but in most cases, it is caused by a bad voltage regulator. So, when this starts happening on your car, you should check the regulator and possibly replace it – replacing the regulator is not an expensive service to get done for you.’

6. Power Dips While Driving

There are many components of the engine controlled by electronic charge – this includes spark plugs, the fuel pump, AC units, and many others. Particularly, the fuel pump may not function properly when there’s an issue with the car’s electrical system. This can cause intermittent dips in power while driving, due to improper fuel supply to the combustion chamber.

A voltage regulator will cause more problems in a hybrid vehicle, or modern cars that are equipped with so many computerized components. Again, malfunctioning of the fuel pump and other electrical components of the car isn’t basically caused by a bad voltage regulator. There could be other causes – use an OBDII scanner to check the car.

How Does a Voltage Regulator Work?

When you get into a car and turn the ignition switch, which is supposed to start the car, a process kicks off immediately – the ignition process. At the turn of the ignition switch, voltage moves from the car’s battery to the starter motor to crank the drivetrain/powertrain components for the car to move.

The moment the drivetrain/powertrain components are triggered, the car would then start and drive. But then, that moment you turn the ignition switch, electrical current from the switch through an electronic voltage regulator (connected to the alternator) gets to the battery, which then powers every other necessary part of the car for it to start moving.

The regulator comprises components such as transistors, diodes, and several other small components. These components are what turns the alternator on or off to regulate voltage output from the magnetic field circuit where the electrical power generation start in every car.

Looking at this process, it seems like it’d take a lot of time for everything to run through, but no, all these happen in split seconds. The regulator delivers 13.5V current to the 12V battery in most cars, and once the voltage supply reaches 14.5V, the regulator disconnects to avoid delivering high power that may damage your car’s electrical components and devices.

Frequently Asked Questions

How Do You Test a Voltage Regulator?

The simplest method for a DIYer is to use an auto-scanning tool like the popular OBDII scanner to troubleshoot the car and look out for DTCs. Also, you could use a digital multimeter (DMM) to test the charging system output of the battery.

Manual testing with a DDM means connecting the black meter lead (of the multimeter) to the battery’s negative terminal and the red meter lead to the positive terminal while the engine is turned off and checking the reading. It should be reading at least 12.2V; if too low, the voltage regulator is possibly faulty.

Where’s the Voltage Regulator Located?

It is installed around the alternator – the exact location differs in different vehicles. However, it is mostly located inside the alternator assembly or at the back of the alternator. On the other hand, some newer vehicles have the regulator integrated into the Engine Control Unit (ECU).

How Much Does it Cost to Replace a Bad Voltage Regulator?

Replacing a bad voltage regulator is one of the least expensive repairs to do on a vehicle. Parts costs are around $80 to $350, depending on your car make and model, while labor costs are around $50 to $100 or higher, depending on the workshop you’re getting it done in.

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