Turning on your car might be impossible if the battery is bad or weak. The battery provides power to the starter, which switches the engine on. However, cars sometimes fail to start even when the battery is good.
If a car doesn’t start, but the battery is good, there may be a problem with its electrical system. The problem could be an issue with the starter, wiring, alternator, or sensors. This prevents the battery from supplying the power needed to crank the engine.
This article will explain why a car won’t start if the battery is good and provide possible solutions to get your vehicle started again. Read on to learn more about them and ways to diagnose if you’re having a starter or battery problem.
Why Would a Car Not Start if the Battery Is Good?
If a car’s battery is good, but the vehicle won’t start, it could be a bad starter, a bad alternator, a problem with the electrical system, or even something as simple as a dirty battery terminal. Also, a faulty ignition switch could prevent a car from starting.
Here’s a rundown of some of the reasons your car won’t start despite having a good battery:
The Starter Is Damaged
Your starter is a small electric motor-generator inside your vehicle’s engine. It turns the engine over or rotates it so that the pistons in the cylinders move up and down, which allows fuel to combust inside them. It’s similar to how a hand crank in old cars would turn the engine over.
When your starter malfunctions, it can prevent your vehicle from turning on. Your vehicle might start if you turn the key but fail to keep running after releasing the key or stop pressing on the gas pedal. Often, a faulty starter will require replacement.
The Battery Is Loosely Connected
If your battery isn’t properly connected, then there won’t be enough power getting to it. As a result, you won’t get any electricity flowing through it when you turn on the ignition switch; thus, your car won’t start up or stay turned on. A loose connection isn’t only one of the common causes of a vehicle not starting but also one of the most overlooked.
The Alternator Isn’t Charging
Your battery has to be connected to an alternator for it to charge. If your car’s alternator isn’t working, then the battery won’t get recharged and eventually go flat or fail to power the starter motor.
Then, your vehicle won’t stay on when you turn on the ignition key. You’ll notice that your dashboard lights dim or blink when this happens.
The Ignition Switch Is Faul
A faulty ignition switch can prevent the car from starting and keep it from staying powered up when you turn on the key. The main symptom of an ignition problem is that the starter will operate, but not much else happens; accessories like power windows don’t work, and headlights fail to come on as well. This could be due to corrosion in the switch or electrical problems such as broken or shorted wires.
A qualified technician will need to diagnose and repair any issues with the ignition system to get your vehicle running again.
Electrical Issues in the Car
Sometimes, a car won’t start up because of electrical problems in the vehicle. This can be due to defective fuses and relays, badly grounded electrical systems (such as rusted grounding points), and issues with the computer.
A qualified technician will need to diagnose the electrical system to identify what’s wrong with it and fix any issues as required before a car can start up again.
What Do I Do if My Car Won’t Start but the Battery Works?
Suppose your car won’t start, but the battery works. In that case, you should replace the starter, check the alternator, ensure the battery is connected properly, or troubleshoot if there are other electrical issues. If these fixes don’t work, call a professional mechanic to help.
I’ll describe how to go about these fixes in detail below:
Replace the Starter
As mentioned above, you can solve the problem of your car not starting by replacing the starter. Here’s how to replace your car’s starter in 5 easy steps:
- Disconnect the battery cables from the battery.
- Remove the starter from your car’s engine bay by disconnecting the wiring from it.
- Install a new starter in your car’s engine bay by putting the wiring into it and bolting it back where it was before.
- Reconnect the battery cables to your car’s battery.
- Test to see if you’ve solved the problem by turning on the ignition switch. If it still doesn’t start up, then there may be another issue with your car.
Check the Alternator
If replacing the starter doesn’t work and you still can’t get your car’s engine to turn on, you should check if it’s the battery or alternator that isn’t working.
Use a multimeter to test if your alternator is charging correctly by checking if it puts out 13–14 volts. If you see a reading much less than this, you have an alternator problem. Here’s a YouTube video on how to test a car’s alternator:
Ensure the Battery Is Connected Properly
If your car won’t start and you’ve tested the alternator and found that it works, then you should check if the battery is connected properly.
- The positive cable has a firm connection.
- There’s no corrosion on the cables or terminals (clean with a wire brush).
- The negative cable has a firm connection.
- The battery tray is secure in the engine bay.
Tighten the terminal connections if there’s any corrosion and clean them with a wire brush before reconnecting to their respective terminals.
Here’s a helpful YouTube video that shows you how to do this:
Check for Other Electrical Issues
If you’ve checked the starter, alternator, and battery connections as described above, and all of those are fine, then there may be problems with your car’s electrical system. Some of these issues could be sensor problems, damaged engine parts, or other serious problems that need to be diagnosed and fixed by a professional.
In such cases, you should bring your car to a professional technician to diagnose and fix any electrical issues causing your car not to start. The mechanic may also look at other factors that can affect the performance of your car’s electrical system, such as battery age and how often you use it in cold weather.
Frequently Asked Questions
Here are some of the most common questions about car batteries and why your car won’t start.
Can a Battery Be Fully Charged and Still Be Bad?
In general, a battery can be fully charged and still be bad. Although such batteries may seem like they work fine, they may not be able to provide enough power for your car’s engine as it gets older. This can cause your car to turn off randomly when driving, leaving you stranded.
In fact, a battery near the end of its life could be almost fully charged but still not run the vehicle properly due to its age. Therefore, I recommend getting a battery load tester. It allows you to test your car’s battery’s ability to hold a charge and turn over the engine. It can tell you if your battery is weak or about to go bad, so you’ll know when it needs to be replaced.
How Do I Know if It’s My Battery or My Starter?
If you’re having trouble starting your car, the problem may be either your battery or your starter. But how can you tell which one is the culprit?
If your car won’t start and the lights are dim when you try to turn it on, it’s probably your battery. If it takes a long time for your car to start, but the lights are bright when you turn on the ignition, it’s perhaps your starter.
However, to be sure which one is faulty, I recommend that you have a mechanic inspect your car’s electrical system.
- A car that won’t start but the battery is good may have electrical problems.
- Typical areas to check include the starter, alternator, and ignition switch.
- Also, check your battery’s connection and clean it if there are any signs of corrosion.
- Another problem is your battery might be too old and has lost its ability to hold a charge.
- Check with a mechanic if you suspect an electrical issue — they can test the starter, alternator, and ignition switch and recommend the next steps.