Imagine you’re cruising down the highway, wind in your hair, tunes on the radio, and suddenly, your dashboard lights up like a Christmas tree. The engine sputters, the power steering feels heavy, and panic sets in. What could be causing this sudden chaos? Could it be the alternator?
The alternator is one of the most important parts of the car that should not be joked about. It is powerful because it powers the engine as well as the electrical components of the vehicle.
Just like other car parts, the alternator can go bad. I’ve had an alternator issue in my Lexus IS350 and I know how frustrating it was until I got it fixed. Therefore, what happens when an alternator goes out while driving?
When your car’s alternator goes out while driving, you will experience:
- Loss of electrical power
- Engine stalling and misfiring
- Loss of power steering and braking assistance
- Warning lights on the dashboard
- Overheating
What Happens When an Alternator Goes Out While Driving?
Here’s what happens when your alternator goes out while you’re driving:
1. You Will Loose Electrical Power
Loss of electrical power is one of the most immediate and noticeable effects of a failing alternator while driving because the alternator is responsible for charging the battery while the engine is running.
If it fails, the electrical systems in your vehicle will start drawing power directly from the battery. As a result, you may notice dimming lights, loss of power to electronic systems (such as power windows and door locks), and the eventual complete loss of electrical power as the battery drains to a complete death.
Furthermore, the heating, ventilation, and air conditioning (HVAC) systems may cease to operate because the alternator provides power to the blower motor and other HVAC components.
Gauges and indicators on the instrument cluster, such as the speedometer, fuel gauge, and temperature gauge, may stop working or behave erratically.
When an alternator goes out while driving, it’s a matter of time before the car stalls and dies. Once the engine must have used up the charged battery, the car will die or turn off on its own.
2. You Will Experience Engine Stalling or Misfiring
If the alternator goes out while you’re driving, the engine may experience irregularities such as stalling, misfiring, or difficulty starting.
Since the alternator is responsible for providing electrical power to the ignition system, which generates the spark needed to ignite the air-fuel mixture in the engine cylinders, when the alternator fails, the battery alone may not provide sufficient power to maintain proper ignition, leading to engine misfires or stalling.
If your vehicle uses an electronic fuel injection systems, which rely on the alternator for power, and the alternator fails, the fuel injection system may not function correctly, causing the engine to receive either too much or too little fuel, resulting in misfires or stalling.
Moreover, the ECM relies on electrical power from the alternator to monitor and regulate various engine functions, including fuel delivery and ignition timing.
A failing alternator can derange communication between the ECM and other engine components, leading to erratic behavior such as stalling or misfiring.
Also, many sensors throughout the engine and exhaust system provide feedback to the ECM, allowing it to adjust fuel delivery and ignition timing for an ideal performance.
If your alternator goes out while driving, these sensors may not function correctly, thereby, causing the ECM to make incorrect adjustments that will result in stalling or misfiring.
3. There Will be Warning Lights on the Dashboard
When the alternator goes out while driving, it will cause the illumination of warning lights on the vehicle’s dashboard. You’ll likely see the battery warning light or the alternator warning light illuminating on your dashboard.
The battery warning light will come on to show that the vehicle’s battery is not receiving sufficient charge from the alternator. It may also indicate other issues related to the battery, such as low voltage or a malfunctioning charging system.
The alternator warning light may also come on to alert the driver of a problem with the charging system. This light serves as a direct indicator of alternator failure or malfunction.
4. Loss of Power Steering and Braking Assistance
When the alternator fails while driving, it can lead to the loss of power steering and braking assistance in some vehicles. This is when your steering becomes too heavy and strong to steer. You may have to use all your energy to turn the steering.
For example, some vehicles are equipped with electric power steering (EPS) systems that rely on the alternator to function. The alternator generates electrical power necessary to assist the power steering system in providing effortless steering control.
When the alternator fails, the power steering system may lose its electrical assistance, making it harder for the driver to turn the steering wheel, especially at lower speeds or when parking.
Nevertheless, some vehicles use electrically assisted braking systems, such as electric power brakes or brake-by-wire systems, which also rely on the alternator for power.
If the alternator goes out while driving, these braking systems may lose their power assistance, requiring the driver to apply more force to the brake pedal to achieve the same braking performance.
Doing this in the middle of the road can result in longer stopping distances and compromise safety, especially in emergency braking situations.
Therefore, it is wise to say that the loss of power steering and braking assistance occurs because the alternator failure interrupts the supply of electrical power to the systems responsible for these functions.
5. The Engine May Overheat
When the alternator goes out while driving, it can lead to overheating of the engine. This is possible because the alternator is responsible for providing electrical power to the cooling fan, which helps regulate the engine’s temperature by dissipating excess heat.
If the alternator fails, the cooling fan may stop functioning or operate intermittently, reducing its ability to cool the engine efficiently.
In some vehicles, the alternator also powers auxiliary cooling systems or components that help manage engine temperature, such as coolant circulation pumps.
When the alternator fails, these auxiliary systems may cease to function, leading to inadequate cooling and overheating of the engine.
Moreover, once the alternator goes out while you’re driving, your vehicle’s electrical systems will start drawing power directly from the battery, which increases the load on the battery, and in turn, places additional strain on the engine’s charging system.
The engine must work harder to compensate for the increased electrical demand, which can generate more heat.
6. The Car Will Shut Off
When the alternator goes out while driving, it can lead to the car shutting off. It’s only a matter of time before the car shuts off.
As reiterated earlier, the alternator is responsible for charging the battery while the engine is running. If the alternator fails, the electrical systems in the vehicle start drawing power directly from the battery.
As the battery loses its charge, the electrical systems responsible for engine operation like the fuel injection system and ignition system, may begin to malfunction or shut down entirely.
The engine will start by stalling which can happen suddenly without warning, as the engine loses the power it needs to continue running.
Without the alternator to maintain electrical power, the engine cannot sustain operation, resulting in a complete shutdown which may lead to loss of control of the vehicle and increase the risk of accidents, especially if it occurs in traffic or at high speeds.
What to Do If Alternator Dies While Driving
Here’s what to do if your alternator goes out while driving:
- Turn Off Non-Important Electrical Components: As soon as you notice signs of alternator failure while driving, such as dashboard warning lights or dimming headlights, start conserving battery power by turning off any unnecessary electrical systems, including the radio, air conditioning, and interior lights or ambient lights.
- Avoid Sudden Movements: With a failing alternator, your vehicle’s electrical and mechanical systems may become unpredictable. Drive cautiously and avoid sudden acceleration, braking, or steering maneuvers, especially if the power steering assistance is affected.
- Find a Safe Place to Pull Over: Look for the nearest safe location to pull over, such as a parking lot, or rest area. Use your turn signals to indicate your intention to pull over, and be mindful of other vehicles on the road.
- Check What Happened to the Alternator: Once you’ve safely stopped, assess the extent of the alternator failure and its impact on your vehicle. Check for any visible signs of damage or leaks under the hood, but avoid opening the hood if you’re unsure about your safety or lack the necessary expertise.
However, if you’re unable to diagnose or resolve the alternator issue yourself, it’s best to call for roadside assistance or a tow truck.
Most roadside assistance services offer battery jump-starts, alternator replacements, or towing to a nearby repair shop where the alternator will be diagnosed and fixed/replaced.
How Long Will a Car Run With a Bad Alternator?
The length of time a car can run with a bad alternator depends on the condition of the battery, the electrical load on the vehicle, and the driving conditions.
Generally, a car can continue to run for a limited time with a bad alternator, but its ability to operate will be progressively impaired as the battery drains.
When an alternator fails, the vehicle’s electrical system relies solely on the battery for power. Most car batteries are designed to provide enough energy to start the engine and power essential systems for a short period, around 30 minutes to an hour, depending on several factors.
However, as the battery continues to power the vehicle’s electrical components, such as lights, radio, and ignition systems, it will gradually deplete. Once the battery’s charge is depleted, the car will no longer be able to start, and the engine will shut off.
Furthermore, the duration for which a car can run with a bad alternator may also be affected by factors such as driving speed, weather conditions, and the age and condition of the battery.
For example, driving at higher speeds or in stop-and-go traffic can place a greater strain on the battery and fasten its depletion.
Also, extreme temperatures, both hot and cold, can affect battery performance and reduce its ability to hold a charge. Therefore, older batteries or those with existing issues may drain more quickly when subjected to the increased demand caused by a failing alternator.
Conclusion
Having a failed alternator while driving is something you should not wish even your worst enemy. However, if your alternator fails while you’re driving, you will experience loss of power, the battery and an alternator warning light may come on on your dashboard, you will experience loss of power steering and braking assistance if your vehicle uses an electric steering, and, you may also experience stalling and misfiring.
