Bad Voltage Regulator Symptoms

Bad Voltage Regulator Symptoms – A Shockingly Nasty Problem?

If there’s one side to the inner workings of a car that we sometimes tend to forget, it’s that there are other vital consumables besides fuel. Your battery, for instance, provides a power source for all that gasoline and diesel to combust, hence creating power. Given its importance, it’s beyond a necessity that we understand these electrics, such as what goes behind bad voltage regulator symptoms.

Your car doesn’t just need a spark for the engine to run, mind you. Electricity runs across the length of your car, powering everything from vital parts such as the head- and tail-lights. Also, there are the auxiliary components such as the radio and heated seats, or safety kits such as the airbags. When those parts stop getting their quota of electrons, they can stop working in an instant.

This could, at the very least, prevent your car from working properly. It may cause some discomfort, or even put your life in danger. It’s, therefore, a must that we should diagnose faults within your car’s electrical system in a pinch, such as being able to identify bad voltage regulator symptoms. Here’s all that you need to know to get started…

What Do You Need To Know About Your Car’s Voltage Regulator?

Before we can look in-depth at the bad voltage regulator symptoms, we should first get to grips with what this component in question does in your car. However, and prior to learning more of the role it plays, we need to do a quick refresh on how electricity is generated. To be more specific, how can a car have a seemingly steady, and almost endless stream of electrons passing along?

This is thanks to the work of two components – the battery and the alternator. The battery, as we’ve become familiar with, is the source of your car’s electric supply. Most vehicles have a 12V battery, or thereabouts. Meanwhile, larger vehicles such as semi-trucks or buses could have double that voltage output for their batteries respectively, at around 24 or so volts.

Nevertheless, mankind doesn’t yet have a battery technology that could last the average five years full of charge that a 12V car battery could provide. So, how does it do this? This is where your car’s alternator comes in. You can think of it as a sort of small generator. The alternator is driven by the engine through a belt, and it continually runs while your engine is turned on.

This way, the alternator will gradually recharge your vehicle’s battery, be it 12V or otherwise, and keep it topped up. With this in mind, many technicians have argued, and regard the alternator as the true source of electricity in a car. The battery, on the other hand, is merely temporary storage. It thus allows the alternator and battery to work together to perpetually supply electricity.

How Does A Voltage Regulator Work?

There is, unfortunately, a problem with that one-way system. The battery is quite a sensitive unit, so it’s unwise to supply either too much, or too little electricity. Should the alternator, for instance, had been left to its own devices, the amount of voltage it supplies may not be evenly distributed back to the battery. In other words, the voltage output of the alternator isn’t uniform.

The battery has no choice but to take all these volts in. Yet, if the alternator outputs a voltage that’s too high, it could badly damage and wear out the battery. On the flip side, if the alternator outputs too low of a voltage, it might not be enough to keep the battery charged. This is where our friend, the voltage regulator, swoops in to moderate the alternator’s voltage output.

In a car, the voltage regulator limits the output to a happy place between 13.5 to 14.5 volts. This is a good sweet spot, where the battery can be sufficiently charged up, without causing extensive wear or damage. The latter not only affect the battery, but also the rest of your car’s electrics, such as the wiring, lights, motors, solenoids, fuses, electronics, interior accessories, and so on.

Where Can You Find The Voltage Regulator?

The voltage regulator is often fitted as a part of the alternator unit, though older cars might have it as a separate unit. Anytime the alternator generates electricity, that current flows first through the voltage regulator before it reaches the battery. If the voltage in the system is too low (below 13.5V), the regulator has sensors that could close the circuit between the alternator and battery.

This should send a burst of current to the field terminal of the alternator, which prompts it to switch on and charge up the battery back to its nominal voltage charge. Voltage regulators are often made as electromechanical components back in the olden days. This means that it can actuate a physical break in the circuity to stop or continue the flow of electricity.

In modern cars, however, these parts rely on electronic units to actuate and thus halt or proceed with the flow of voltage. Now, if the voltage is perhaps a bit too high (above 14.5V), the regulator can switch off the flow of current from the alternator completely. This prevents it from providing electricity to the battery and avoids it from being overcharged, where it could burn out or explode.

What’s Causing It To Exhibit Bad Voltage Regulator Symptoms?

Commonly, your car’s voltage regulator is made to be robust and dependable, which could easily last the lifetime of your car. Bearing that in mind, it’s quite unlikely that you’ll come across bad voltage regulator symptoms. However, they can still fail over time and exhibit those tell-tale signs of failure. Here are some of the factors that cause your voltage regulator to wear out and fail:

  • Intense heat exposure is emitted from the alternator, engine, and surrounding componentry that may wear out the regulator’s internal components.
  • A diode inside the voltage regulator could fail, causing it to “leak” current, and drain it away from the battery. This usually happens if the vehicle hasn’t been driven in a long time.
  • That diode may also short itself, if there’s too much forward current and reverse voltage. This causes the diode to burn out.
  • The continuous draw of electricity, such as forgetting to turn off your lights, could wear out the regulator much faster.
  • Trying to drive with a faulty battery (or with no battery installed) can cause huge ignition spikes, as the circuit could create as much as 400V. This is enough to blow the regulator.
  • A faulty alternator may constantly wear the voltage regulator through uneven outputs of voltage to the regulator.

What Are The Bad Voltage Regulator Symptoms That You Should Look Out For?

With that out of the way, we can now get into discussing the actual bad voltage regulator symptoms that you could spot. These are tell-tale signs that the voltage regulator is either on its way out, or it has already failed. In any case, you should take these seriously. Trying to ignore any of the following bad voltage regulator symptoms is (quite literally) playing with fire.

It’s not worth the risk, as to keep on driving with a faulty or failed voltage regulator could raise what is a relatively inexpensive repair, into a disastrous one. Your battery could explode, or else parts such as the lights or the electrical system could burn out or fry. To prevent yourself from having to worry about the side effects of ignoring a poor voltage regulator, here’s what to look out for:

1. The Check Engine Light Or Battery Warning Light Comes On

Thankfully, our modern automobiles are rather quick at alerting us of potential issues, be it electrical or mechanical in nature. Once faults appear or seem to be appearing, your car can throw in any one warning light to let you know and ensures that you have enough time to deal with it.

For bad voltage regulator symptoms, there are two lights that may appear. These may either be the check engine light or the battery warning light. With the check engine light, you could use an OBD diagnostics tool to scan for any trouble codes and see if they relate to voltage problems.

Here are some of the OBD diagnostics trouble codes (DTC) that may concern the voltage regulator:

  • P0560 – System Voltage Malfunction
  • P0561 – System Voltage Unstable
  • P0562 – System Voltage Low
  • P0563 – System Voltage High
  • P2502 – Charging System Voltage
  • P2503 – Charging System Voltage Low
  • P2504 – Charging System Voltage High

Bad Voltage Regulator Symptoms

If you’re getting a battery warning light instead, you could try doing a voltage check with a simple multimeter tool. We’ll get into diagnosing bad voltage regulator symptoms later on in this guide.

2. Your Battery Is Dead

Your car’s battery could die from many potential variables. The battery itself may have been old, and it’s unable to supply a sufficient amount of charge. Or, it could be caused by a parasitic drain, as you forgot to turn off your headlights as you exit the car.

Additionally, and more relevantly, it may have died due to a poorly managed supply of current owing to a faulty (or utterly failed) voltage regulator. Once that regulator isn’t working right anymore, it can’t be expected to supply an adequate amount of voltage to keep the battery charged.

3. The Lights Are Either Dimming Or Are Flickering

The electric system on your car could easily be diagnosed for faults just by inspecting how the many parts connected to it are working. The most visible item is no doubt the lights, commonly either the headlights or the dome lights, if you prefer to stay inside.

Are they dimming, or are dimmer than when you last left it? Or, could they be flickering on and off? In this case, it’s a sign that your electrics aren’t supplying enough voltage to keep them running. As for the flickering, the voltage is present but isn’t uniformly supplied for it to work consistently.

Battery- and alternator-related issues could result in these dimming and flickering lights appearing. However, we can also narrow down the point of failure to a bad voltage regulator. Other accessories might also exhibit odd signs of malfunction, such as the stereo intermittently turning on and off.

The high beams are another good way to test if the voltage output is working well, or not. The high beams take up a lot of power to run. If they won’t light up properly or are a lot dimmer than you last remembered, then there’s a fault somewhere with the electrical flow.

4. The Instrument Cluster Isn’t Turning On

We spoke of warning lights earlier, which could lead you towards the first clear sign of bad voltage regulator symptoms. But what if the lights aren’t even visible… What if the entire instrument cluster isn’t turning on? As with every other electrical part, the instrument cluster needs current.

A steady stream of voltage is sent to keep it working, as it displays all the information you need as you drive along. Should your voltage regulator be on its way out, the electrical system might not be able to provide enough electricity.

In this scenario, the instrument cluster won’t light up at all or might behave oddly. For instance, it could turn itself on and off repeatedly. That low or sporadic output of voltage might even prevent your car from starting, as it’s now affected the ignition system.

But let’s say the car does start up, it’s not entirely a good idea to keep on driving, is it? After all, with a non-functioning dash, you can’t see how fast you’re going, or how much fuel you have left. The dangers would rapidly intensify at night, where the dash can’t light ambient lighting.

5. You Have Burnt Out Lights

So far, we’ve talked a lot about how bad voltage regulator symptoms crop up when the voltage is too low. But what happens when the volts are too high? A car battery is typically rated at 12.6V when it’s idle. Once the car starts running, the voltage should measure around 2V higher.

Headlights burnt out over too high voltage

At most, the battery could only take in 16V. Any higher, and it can cause damage to the battery – such as it literally exploding – or to your car’s other electrical components. That high voltage can fry the wiring and fuses, for example, and overload the rest of the system.

The most common and noticeable symptom of there being too much voltage, however, is burnt-out lights. Your headlights and taillights would prematurely need service, as the high voltage can start with burning the bulbs out rather rapidly.

6. The Car Exhibits Poor Performance

The uneven or erratic output of voltage won’t just affect the lights or your stereo. Remember that most of your car relies on some electrical current. The spark plugs need a tiny burst of electrons for it to ignite the fuel, while various other parts require electricity, too.

These include numerous pumps (fuel, water, oil, etc.), the thermostat, countless sensors (O2, mass airflow, crankshaft positioning, vehicle speed, wheel speed, etc.), the ignition switch, your electronic throttle control, and endless more components here and there.

If the voltage output is too low, these components would naturally misbehave and are unable to perform their various functions. Your car’s performance, as a result, will suffer, and you can notice things such as delayed acceleration, a rough idle, stalling, or your engine sputtering or misfiring.

How Can You Test And Diagnose These Bad Voltage Regulator Symptoms?

So far, we’ve delved into the bad voltage regulator symptoms. As we can see, it can turn out to be fairly serious. It can leave most of your car paralyzed, as their sole electrical lifeline is unable to provide the bare minimum voltage for them to work. Elsewhere, having your electrics supply too much voltage is more than enough to cause them to malfunction, or fail altogether.

A failed voltage regulator is downright deadly, as well. Your car may die out on you in the middle of your drive, just in time as the safety systems such as airbags or automated braking stop working. There’s now a fire hazard, as your faulty voltage regulator may lead to the battery overcharging, and later exploding or burning once it gets too full.

Nevertheless, these symptoms could be shown by faults elsewhere in your car’s electrical system, rather than it being a bad voltage regulator. This is why it’s important that we conduct a proper and thorough diagnosis. This allows us to ascertain whether they are, or are not caused by the voltage regulator. If you’re curious, here is a quick guide on how you can test it…

Step-By-Step Guide To Test The Voltage Regulator:

  1. First, check the rest of the electrics to make sure they’re not the ones at fault. These include seeing if the battery connections are clean and secured. On top of that, check if the battery cables are in good condition, with healthy ground connections, and that the serpentine (or drive) belt is working right.
  2. If all’s well on that end, you can begin testing the voltage regulator with a digital multimeter. Before you get started, safely park your car, and keep it in Neutral or Park.
  3. Now, set the multimeter to read “DC Voltage”, and pick 20V (volts) in the scale.
  4. Then, connect the multimeter’s red lead to your battery’s positive (+) terminal, and the black lead goes to the battery’s negative (-) terminal.
  5. Next up, get someone to help you start the car up, and let it run at around 1,500RPM.
  6. This way, you can get an accurate reading on your multimeter. Remember, the battery’s output is rated at 12.6V or 12.4 volts at the bare minimum. With the engine now running, the voltage reading ought to be 2V higher, at around 14.6V.
  7. If the voltage reading is lower than 13V or is higher than 16V with the engine running in both instances, there’s certainly a fault with the voltage regulator.

How Much Does Bad Voltage Regulator Symptoms Cost To Fix?

Now that you’ve figured out that you have a faulty voltage regulator, what can you do to make all the bad voltage regulator symptoms go away? For the most part, the only long-lasting solution is to replace the regulator outright. This is relatively inexpensive compared to fixing up collateral damage should you keep on driving with a poor or failed voltage regulator.

Bear in mind that a new alternator costs $200 to $500 just for the unit itself. Swapping the burnt-out wires and fuses, or getting a new battery, aren’t cheap either. By comparison, a prompt replacement of the voltage regulator will set you back around $70 to $400. Of course, the total repair bill will vary significantly depending on the type, make, and model of your vehicle.

Primarily, we have to look at how complex it is to replace the regulator. Plus, whether you’d be opting to get OEM or aftermarket regulators. The part costs around $20 to $200 on average. Labour, on the other hand, is another $50 to $200. Your mechanic will almost always charge a lofty fee to replace the regulator, as the voltage regulators are often mounted inside the alternator.

If it’s fitted outside the alternator, it should be easier to get at, and thus cheaper as far as overall complexity goes. In some vehicles, the voltage regulator is an integral part of the alternator. This means that you basically have to replace the entire alternator unit, even if just the regulator alone is faulty. Unfortunately, this will jack up the repair bills by a huge degree.

Bad Voltage Regulator Symptoms – Conclusion

In all, that rounds up our look at bad voltage regulator symptoms. They can be quite subtle, as we’ve learned, since their symptoms are similar to that of a failing alternator, or if your battery is getting a bit old. That’s why it’s crucial that you’re also well acquainted with diagnosing the fault at hand. This is to see if the voltage regulator is truly the cause of these symptoms to appear.

Otherwise, misdiagnosing can lead to costly consequences. While not the cheapest fix in the world, a bill of around $70 to $400 isn’t terrible in the world of automotive repairs. In fact, we can consider it to be comparatively cheap, given how vital the role of the voltage regulator is. Should you ignore it instead, you could be quietly be racking up more extensive damage elsewhere on your car.

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