Electrical problems can be some of the toughest nuts to crack when it comes to automotive diagnostics, but there are really only a couple of potential issues that could cause a car’s electrical system to totally shut down and then suddenly start working again.
If you haven’t done any diagnostic work at all, and you’re comfortable checking out a few basic things, then you’ll want to start with the car battery.
Loose battery connections can cause an electrical system to “shut down” and then start working again, as can bad fusible links, so the connections between the battery and the rest of the electric system should be checked out thoroughly before anything else.
Other than that, a problem with the ignition switch can also cause this type of problem. If the problem runs any deeper than that, then a professional will probably have to take a look at the vehicle.
Reasons For a Car to Suddenly Lose Electrical Power
Here are the main components that can cause a car to lose electrical power:
|What It Does||What Does a Failure Look Like?|
|Alternator||Provides power while the engine is running.||Lights will typically dim, and the engine may die.|
|Battery||Provides power necessary to start the vehicle, and powers accessories when the engine is off.||The vehicle won't start at all, or will crank slowly. Driving a car with a dead battery can also damage the alternator.|
|Fuses and fusible links||Provide a failsafe if something draws too much current.||The engine may not start, or you may suddenly lose all electrical power while driving.|
|Ignition coil and other ignition components||Provides power to the spark plugs, and increases the voltage of the power provided to the spark plugs.||The engine may not start, or it may die while you're driving. Electrical power will still be available, so your lights and radio will still function.|
|Starter, starter solenoid, or relay||Physically rotates internal engine components until the process of internal combustion can take over.||The engine won't start. A bad starter, solenoid, or relay won't cause a loss of electrical power.|
Breaking Down What Went Wrong
In modern gasoline and diesel vehicles, electrical power can come from two places: the battery and an alternator.
The battery stores power, which your vehicle uses to perform three basic functions: starting the engine, running accessories when the engine is off, and powering the alternator’s voltage regulator.
The purpose of the alternator is to generate electricity to run everything from your headlights to your head while the engine is running. This is why adding a second battery provides you with more power when the car is off and upgrading to a high output alternator helps when it's on.
If you’re driving along, and everything suddenly goes dead—no dash lights, no radio, no interior lights, no nothing—that means that power isn’t getting to any of those components. If the engine itself dies as well, that means the ignition system itself isn’t receiving power either.
When everything suddenly starts working again, that just means that the momentary fault has passed, and power has been restored.
But what can cause the power to be cut off like that?
Bad Battery Cables and Fusible Links
The battery connections should always be the first suspect in this type of a situation, both because they are the likely culprit, and because they are relatively easy to check.
If you find a loose connection on either the positive or negative cable, then you will want to tighten it up. If you notice a lot of corrosion at the battery terminals, then you may want to clean both the terminals and the cable ends before tightening everything up.
In addition to checking the connections at the battery, you can also trace both the positive and negative cables to make sure that things are tight on the other ends as well.
The negative cable will typically bolt up to the frame, so you’ll want to check for rust and make sure the connection is tight. The positive cable will typically connect to a junction block or main fuse block, and you can check those connections as well.
Some vehicles use fusible links, which are special wires that are designed to act like fuses and blow in order to protect other components. These are necessary and valuable components in the situations where they are used, but the issue is that fusible links can become brittle and somewhat less than pliable as they age.
If your vehicle has any fusible links, you may want to check their condition, or just replace them if they are old and haven’t ever been replaced, and then see if that fixes the issue.
If the battery connections are fine, and you don’t have any fusible links, there are situations where a bad main fuse could cause this type of issue, although fuses typically don’t fail and then just start working again like magic.
Checking the Ignition Switch
A bad ignition switch is another likely culprit, although checking and replacing one is a little more complicated than tightening battery cables.
The electrical portion of your ignition switch will typically be located somewhere in the steering column or dash, and you may have to disassemble a variety of trim pieces to even gain access to it.
If you are able to gain access to your ignition switch, then a visual inspect that reveals any burnt wires is indicative of the type of problem that can cause a vehicle’s electrical system to suddenly cut out and then start working again.
Since the ignition switch provides power to both accessories like your radio and your vehicle’s ignition system, a bad switch can definitely cause both to suddenly stop working. The fix is to simply replace the bad switch, which is usually pretty easy once you’ve done the work of gaining access to it in the first place.
Other ignition components, like the coil and module, do not cause a vehicle to lose all electrical power when they fail. When these components fail, the engine will die, but you'll still have battery power available to run things like the headlights and radio.
If you're experiencing a problem where the engine died after you've been driving for a while, and then it starts back up after it has cooled down, a bad ignition module may be the culprit. However, you shouldn't suspect the ignition module if you're dealing with a problem where the vehicle loses all electrical power.
Checking the Battery and Alternator
Although this type of problem typically isn’t caused by a bad battery or alternator, there is a small chance that you’re dealing with an alternator that’s on its way out.
The issue would be that the alternator isn’t living up to its rating anymore, which causes the vehicle’s electrical system to run solely on battery power until the battery is dead and everything shuts off.
In rare cases where the alternator then starts working a little better, the electrical system may appear to be in good working order again.
Unfortunately, there aren’t any really easy ways to test a charging system at home. Your best bet, in this case, would be to take your vehicle to a repair shop or a parts store that has the necessary equipment to load test your battery and check the output of your alternator.
If the alternator is no good, then replacing it—and the battery, as running a battery dead repeatedly can cut its life short—may fix your problem.
Was this page helpful?
Thanks for letting us know!
Get the Latest Tech News Delivered Every Day
- A bad alternator. One of the top electrical car issues is a bad alternator. ...
- Dead bar battery. This is one of the most common car electrical issues drivers have. ...
- Spark plug issues. ...
- A blown fuse. ...
- Battery cables need replaced.
An electrical short circuit occurs when there is a fault in your car's wiring. It causes electricity to flow through the wrong path instead of flowing to its intended destination. Short circuits can happen for various reasons, often due to lose connections, damaged insulation, or corroded wires.How do you know if your car has a electrical problem? ›
Have your vehicle's electrical system checked immediately if: Your vehicle won't start - you turn your key and hear clicking, grinding, or no sound at all. Interior or dashboard lights do not illuminate properly. Your vehicle runs well, but the headlights dim while you're traveling at low speeds, or idling at a stop.What would cause a car to be completely dead? ›
If your vehicle won't start, it's usually caused by a dying or dead battery, loose or corroded connection cables, a bad alternator or an issue with the starter. It can be hard to determine if you're dealing with a battery or an alternator problem.Are car electrical problems expensive? ›
Even so, no matter what the job is, a good rule to go by is that you can probably expect to pay at least $200 whenever you need subsantial electrical work done on your car. If you are worried about car repair costs, make sure you have affordable car insurance.What kind of electrical problems can a car have? ›
- Dead Battery. A dead battery is the most common and obvious electrical problem. ...
- Battery Will Not Charge. However, a battery that will no longer hold a charge will need to be replaced. ...
- Bad Alternator. ...
- Fatigued Starter or Solenoid. ...
- Bad Battery Cables. ...
- Blown Electrical Fuses. ...
- Failed Spark Plugs.
Install the adapter and breaker in the fuse box (Photo 1). Then find the short with the meter (Photo 2). Open the wiring harness and locate the chafed or shorted wires and repair them with electrical tape. Reinstall the fuse and test the circuit.How do you test an electrical system in a car? ›
Charging system checks
Set the multi-meter to the correct voltage scale (0 to 20 volts) and connect it across the battery terminals. Start the engine and note the voltage reading, then slowly increase the engine speed up to about 2000rpm, at the same time checking the voltage readings on the meter.
Spotting the electric short:
You can spot an electric short by observing a blown fuse, some sparks, a burning smell with little smoke aided by a little popping sound, a tripping breaker, or solely a popping sound as soon as you turn on any electrical equipment.
Electrical problems can be dangerous in an automobile, especially if the problem involves burning wires. Your car, truck, or C/SUV will give you an indication there's something going on with the electrical system. In most cases, it could just be that the alternator is wearing down and needs to be replaced.
It can cost anywhere from $88 to $111 to get an electrical system diagnosis for your vehicle. Labor costs are estimated to fall within the same range. It's also important to factor in taxes, the type of vehicle you have, and your specific location.How much does it cost to diagnose electrical problems in a car? ›
Diagnosing the actual issue with a mechanic can typically cost anywhere between $85 and $120. This does not include any additional taxes or fees, or any related repairs that might be needed. The cost of repairs can start to add up quickly, but you can always save money on your car insurance plan with the Jerry app.What the problem if the car suddenly stops? ›
Engines usually stop suddenly only if they suffer from a lack of fuel or sparks . An engine that stops dead without prior warning has probably had a sudden ignition failure - although if it locks solid it's more likely to have seized.Why is there absolutely no power in my car despite jump starting it? ›
Your car's ignition switch, alternator, battery, starter, or a fuse could be malfunctioning. Your safety switch could be broken. This switch keeps your transmission from starting unless you're in park or neutral.Why did my car shut off while driving and wont start? ›
A failing fuel pump is one of the faults that can cause this. Other likely problems would be the battery, alternator, battery cable, wiring harness fault, crank or camshaft position sensor. The fuel pump may have been replaced because it was not turning on.How much does it cost to redo electrical in a car? ›
If your car needs to be completely rewired, it can cost you between $1,200 and $1,500. The repair cost will depend on the kind of car, how much wiring there is, and how long it takes to complete repairs.How do you know if your car is worth fixing? ›
Typically, when deciding whether a repair is worthwhile, you should consider the value of the car versus the cost of repairs. A handy rule of thumb is that if the cost of repairing a car costs 50 percent of its value or more, you should consider selling it.Can a weak car battery cause electrical problems? ›
Can a Bad Battery Cause Electrical Problems? Yes, if your battery is underperforming it can cause systems within the vehicle to malfunction. A bad battery can also result in air conditioners, stereos and other applications not receiving enough power to function properly.How do you find a dead short in an electrical system? ›
A dead short is a serious problem, and a tripped breaker can definitely be a sign that you have one. To detect a dead short in your house's wiring, you'll need to test the wires with a multimeter. If you get a reading of 0 ohms, then you have a dead short.How much does it cost to find an electrical short? ›
Finding and repairing a short circuit in your car or truck's electrical system can cost $200 and up at a shop.
- Shorts Occur in a Circuit. Electricity flows in a circuit. ...
- Isolate the Circuit. ...
- Check the Appliances on the Affected Circuit. ...
- You Need the Proper Tools. ...
- Remove the Wires. ...
- Check the Wires. ...
- Remove the Breaker Wires. ...
- Check the Breaker.
Your car's electrical system consists of the battery, starter and alternator. The battery provides juice to the starter. Then, the alternator gives that battery the energy it needs to power your car. If one of these parts is not working properly, your car won't start or run correctly.What are three warning signs of an overloaded electrical circuit? ›
Lights that flicker or dim, especially when you switch on appliances or more lights. Buzzing noises from outlets or switches. Outlet or switch covers that become warm to the touch. Smell of burning from outlets or switches.How does an electrical short happen? ›
An electrical short circuit occurs when a “hot” wire carrying live current comes into contact with a neutral wire, either by touching it directly or through arcing—allowing the current to jump from the live wire to the neutral one.Does AutoZone check electrical system? ›
Every AutoZone in the USA will check your alternator, starter, or battery at no charge.Can AutoZone check for electrical problems? ›
We'll check your alternator, starter, battery and more.
Well, charging systems are the basic electrical system in a vehicle which include an alternator, battery, and voltage regulator. These components are a source of power to other electrical components in the vehicle.Can a mechanic diagnose electrical problems? ›
Due to this fact, most ASE certified mechanics still use the basic probe electrical tester to diagnose most electrical issues found on modern and older vehicles.How long does it take to do an electrical diagnostic on a car? ›
A standard diagnostic test can take about an hour to an hour and a half. Of course, more complicated issues that require further diagnosis and where components must be removed for access or testing can take 2-3 hours; depending on the severity of the issue or multiple underlying issues.What sensors can cause a car not to start? ›
The most common sensors that will stop your car from starting include the camshaft sensor, the crankshaft sensor, the mass air flow (MAF) sensor, the manifold absolute pressure (MAP) sensor and the throttle position sensor.
If the car clicks when trying to start, but still won't start, this can be caused by a weak battery, dirty battery terminals, a worn starter motor or a stuck solenoid. If might just need a jump start, but there are a few tricks to try before breaking out the jumper cables or electric jump starter.What does it mean when your car won't start but the battery is not dead? ›
Broken or Damaged Ignition
If your headlights can turn on, but your car won't crank, that means that your battery is charged, but either the starter or ignition is the problem. If the starter or ignition is the problem, a starter engine can be jumped by using a charged battery.
The most common reason cars don't start is a dead or faulty battery. Even though most cars run on gasoline, they all require electrical power to function. The starter that cranks your engine to start requires an electrical signal to fire. If something's wrong with your battery, your car engine won't turn over.What causes a car to lose power and died while driving? ›
The most likely issue is a clogged fuel filter. The purpose of the fuel filter is to ensure that dirt and debris stay out of the fuel system, so over time, it may need cleaned or replaced. When the fuel filter is clogged, the fuel pump has to work much harder, resulting in a far less efficient drive.What are the 3 electrical faults? ›
There are mainly three types namely line to ground (L-G), line to line (L-L) and double line to ground (LL-G) faults. Line to ground fault (L-G) is most common fault and 65-70 percent of faults are of this type.What are the 4 electrical faults? ›
There are only four possible failures that can take place in an electrical system. These are the open circuit, high resistance, short-to-ground and short-to-power.What are the 2 main faults in electrical? ›
The faults in the power system are mainly categorized into two types: Open Circuit Fault. Short Circuit Fault.What are the 3 types of electrical circuits used in automotive? ›
We will be identifying these items when we look at Automotive Circuits a little later in this book. There are three basic types of circuits: series, parallel, and series-parallel. The type of circuit is determined by how the power source, conductors, loads, and control or protective devices are connected.What is the most common cause of electrical failure? ›
Loose connections are the most common source of electrical equipment failure, causing over 30% of unexpected outages. To help prevent these issues: Check all connections periodically and ensure they are tight.What is the most common cause of electrical problems? ›
It usually occurs due to poor electrical wiring in the house, faulty appliances, damaged power lines, or when lightning strikes. Electrical surges are common electrical problems, and they last for a split of a second. If there are frequent surges, they can damage the equipment and lower its life expectancy.
The different type of faults in power systems are:
- Single line to ground fault (LG)
- Line to line fault (LL)
- Double line to ground fault (LLG)
- Three-phase faults (LLL or LLLG)
- Observation. Look for visual signs of malfunctioning equipment including loose components, parts in the bottom of the cabinet, or signs of overheated components. ...
- Define Problem Areas. ...
- Identify Possible Causes. ...
- Test Probable Cause. ...
- Replace Component and Test Operate.
In an electric power system, a fault or fault current is any abnormal electric current. For example, a short circuit is a fault in which a live wire touches a neutral or ground wire.How do I find a short circuit in my car? ›
Connect one headlight to the battery's positive terminal and connect the other headlight to the battery's negative terminal. Turn on the headlights and check for an electric current, sparks, or heat. If you see any sparks or heat, then you've likely got an electrical short circuit on your hands.