8 Common Electrical Problems in Cars and Repair Costs

Automotive>Maintenance & Repair

May 18, 2023

You think about fuel every time you stop for gas, but you may not consider how much of your vehicle is powered by electricity—even if it has an internal combustion engine. Creature comforts like a radio, heated seats and sunroof, and essentials like power windows, temperature gauges and lights are all powered by your car's electrical system. When something goes wrong with your electrical system, your car won't run right and may not even start.

To ensure that your car is safe and reliable, you need to address electrical problems quickly. It can cost hundreds of dollars (or more!) to fix electrical problems in cars, depending on what's wrong, the type of car and where you live. Here's a breakdown of eight common electrical problems in cars and estimates on how much they cost to fix.

1. Dead battery

Average repair cost: $342-$352 for replacement
The battery is the heart of your car's electrical system—the system can't function without it. Car batteries charge while the engine is running and must hold that charge when the engine is off. Sometimes, batteries drain for obvious reasons, like when you leave the lights on or the stereo playing. In that case, you can jump-start them back to life. However, if your battery isn't able to hold a charge, you'll need to replace it entirely.

Common symptoms: If your battery is dying you may notice:

  • Dim interior lights
  • Engine not turning over immediately
  • Battery warning light turning on when you're driving
  • Car stalling

Causes: Batteries lose efficiency over time. Most car batteries last for about three to five years, so this is a part you'll have to replace regularly.

Tips to prevent dead batteries:

  • Take long trips and run your car regularly. Batteries recharge while the engine is running, so taking regular drives will keep it functioning well.
  • Avoid excessive heat. Heat makes batteries die faster. Unfortunately, there's not too much you can do if you live in a hot climate where batteries generally have shorter lifespans.
  • Secure it tightly. Vibrations can make a battery die quickly. Use hardware to hold your battery in place, and avoid rough roads when possible.

2. Malfunctioning alternator

Average repair cost: $608-$790 for replacement
The alternator is just as essential as the battery. Not only does it recharge the battery, but it also provides electrical power to the car when the engine is running. On a basic level, the alternator converts mechanical energy from the engine into electric energy that powers your lights, sound system and other electronics.

Common symptoms:

  • Power warning lights while you're driving
  • Signs of changes to the electricity supply in the car, like lights that dim and then get bright
  • Electrical components (e.g., the radio or windows) losing power
  • Your vehicle stalling. A jump-start won't restart it.
  • Grinding noise that changes as your speed changes
  • Burnt rubber smell

Causes: Alternators have lots of wearing parts (including bearings and belts) that are under constant strain. It's normal for them to give out over time.

Tips to prevent alternator issues:

  • Get repairs quickly if you notice alternator problems. This could help you avoid a total replacement.
  • Get regular maintenance and have your mechanic check the alternator's condition and components.
  • Don't overload the car's electrical system with too many aftermarket upgrades to the stereo or lighting.

3. Faulty starter motor

Average repair costs: $428-$581 for replacement
The starter motor is a small electric motor that's powered by the battery and turns on the internal combustion engine when you turn the key. If your starter motor isn't working, your engine can't spring to life.

Common symptoms: If your starter motor is dead, you'll hear a clicking noise when you turn your key, but the engine won't turn over. Alternatively, if you hear a whirring noise when you turn the key, you might need to replace the starter solenoid. DIYers can replace the solenoid with repair kits that often cost under $50.

Causes: Starter issues can be caused by faulty wiring, the breakdown of mechanical parts in the starter motor, dirt and rust or even oil leaks. Understanding what caused your starter issue can help you avoid it in the future.

Tips to prevent a faulty starter motor:

  • Control battery corrosion, or replace corroded batteries. The corrosion can spread to the starter, impacting its function
  • Keep your battery and fuses functioning well, and replace them when needed.
  • Avoid stopping and starting frequently, which can wear down the starter.

4. Bad fuse box

Average repair cost: $125 for replacement; less if you DIY
Fuses protect your car's electrical system by melting if too much electricity flows through them. If you blow a fuse, you can replace it for pennies—just make sure you have a fuse that's the same amperage as the one that blew. For ongoing electrical issues, you may need to replace the whole fuse box. Most cars have two—one under the hood and one on the driver's side of the cabin.

Common symptoms: If you blow a fuse, you'll notice that a certain circuit, like the radio, doesn't have power. Signs that you need to replace your fuel box include:

  • Frequently failing fuses
  • Fuses that are loose
  • Broken or bare wires
  • Water stains on the fuse box

Tips to maintain your fuse box:

Fuse boxes don't typically need to be replaced. However, if they fail, they'll bring your entire electrical system down with them. So, it's best to err on the side of caution and talk to a mechanic if you're having lots of issues with fuses.

5. Bad spark plugs

Average repair cost: $207-$264 per plug. Most vehicles have one plug for each cylinder in the engine.
Spark plugs give your vehicle the power it needs by converting electric energy into a spark that ignites the fuel and powers the engine. They kick-start the chain reaction that powers your car, so when they're not working, lots can go wrong.

Common symptoms:

  • Engine trouble, including vibrations and trouble idling
  • “Check engine" light (either flashing or solid)
  • Decreased gas mileage
  • Power surges and drops

Causes: Spark plugs wear out over time.

Tips to maintain your spark plugs:

  • Avoid rough driving habits and harsh road conditions.
  • Address leaking engine fluids that can impact spark plugs.

6. Malfunctioning ignition coils

Average repair cost: $214-$290 per coil; most vehicles have one per cylinder
Ignition coils, also called coil packs, provide electricity to the spark plugs. When ignition coils malfunction, they affect the spark plugs, which can also increase the risk of costly damage to the catalytic converter.

Common symptoms:

  • Engine trouble, including stalling
  • "Check engine light" coming on
  • Sound of rubber band snapping under the hood
  • Car refuses to start
  • Reduced gas mileage

Causes: Engine heat and vibrations can cause ignition coils to break down over time. Malfunctioning spark plugs can lead to the engine getting too much or too little fuel, which can damage the ignition coils.

Tips to maintain ignition coils:

  • Follow the recommended replacement schedule from your vehicle's manufacturer.
  • Replace spark plugs when you notice issues.

7. Wiring problems

Average repair cost: $88-$111 to diagnose and $1,300-$2,000 to repair
Like an electrical system, your car relies on wires to get electricity where it needs to go. When something goes wrong with wiring, even finding the problem can be difficult. Once you know where the trouble lies, you'll need to replace the damaged or broken wires. It can cost up to $2,000 to replace all the wiring in a car.

Common symptoms:

  • Flickering lights or occasional power loss
  • Smell of burning plastic, or other signs of melting or heat
  • Issues with starting your car
  • Frequently blowing fuses

Causes: Anything that interrupts the electrical circuit can lead to wiring problems in a vehicle. Some common causes include rodents chewing on wires, corrosion and wires that come loose over time.

Tips to prevent car wiring issues:

  • Winterize your car if it will be sitting for a while, to avoid rodents.
  • Fix electrical problems promptly.
  • Regularly wash your car, and take note of any loose or damaged wires.

8. Engine control module failure

Average repair cost: $960-$1,035 for replacement
The engine control module is a computer that controls your engine. Without it, the engine won't start. Sometimes, this is called the engine control unit or powertrain control module. No matter what name it goes by, it's essential for modern cars.

Common symptoms:

  • Car won't start
  • "Check engine" light turns on
  • Frequent stalling and poor running when the car does start

Tips for engine control module maintenance:

Although the engine control module should last for the lifetime of the car, it can go bad early, just like any computer. There's not much you can do to prevent this—it's largely a matter of chance.

Financing for car electrical repairs

Electrical problems in cars can quickly stop your vehicle in its tracks. You may find yourself dealing with a relatively mundane issue like a dead battery, a somewhat routine task like spark plug replacement, or a costly random repair like replacing the engine control module.

Since any electrical problems can interfere with your car's reliability and safety, it's important to address them quickly. Having the Synchrony Car CareTM credit card in your wallet can help you manage the unexpected costs of repairing your car's electrical system without delay. Learn more and apply today.

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