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Can You Start a Car with a Bad Alternator?

Can You Start a Car with a Bad Alternator?

Whenever you hear the telltale click of your keys in the ignition but no roar of the engine, you know it’s going to be a tough day. 

Cars can fail to start for a number of reasons, and a bad alternator can be one of them. 

But can we still start the car with a bad alternator?

It is possible to start a car even if it has a faulty alternator, but keep in mind that the car won’t run for very long and you’ll have to take it straight to the mechanic. Otherwise, you run the risk of having your car shut down again.

This article will talk about the symptoms that can indicate alternator failure and the best way to get your car going, even if the alternator isn’t functioning properly. Got to save those calls to AAA!

So, make sure to read this article till the end, otherwise, you might risk getting stranded and not knowing what to do!

Symptoms of a failing alternator

There are several things that can indicate whether an alternator is failing or not. 

However, since the alternator, the battery, and the starter are all closely linked, it might be hard to pinpoint the exact cause. However, there are some ways you can try to narrow down the exact cause.

Dead battery, or failing alternator?

In cases where you can’t start your car, even though you’ve primed the ignition countless times, the cause can fall on the alternator or the battery.

You can check whether the battery is dying by testing the other electrical devices in the car.

If your headlights seem weaker than usual, that may point towards a failing battery, not a failing actuator.

Another method of checking whether it’s a failing actuator or a battery is by jumpstarting the car.

If the car keeps running after your jumpstart the car, this means that your battery might need replacing soon. This is because the battery is mainly used for just giving your alternator a starting jump, and the alternator does the rest.

However, if you start the car, and it dies within a short period of time, this means that the actuator isn’t doing its job properly.

Fluctuation in light

A failing actuator means that unsteady voltage will be delivered to your vehicle’s accessories.

You might note a change in the pressure of your car’s air conditioner, or your headlights might become too dim or too bright. 

This goes for the interior lighting as well.

Electronics might stop working completely

Since a failing actuator fails to deliver the amount of power required, you might notice that several of your car’s electronic accessories have stopped working.

This might include your power window controls, radio, interior lighting, etc. 

Most new cars have it programmed in them to prioritize essential engine components in case of low voltage. 

While the engine may keep running for a little while longer, you might see other non-essential accessories not working.

How to start a car with a bad alternator

Now that we’ve talked about the symptoms of a bad alternator, let’s discuss how we can start a car even if the alternator is failing.

Turn off the car

The first step is to completely shut your car off, and any accessories as well. 

Keep the headlights off, any air conditioning, or any other electronic devices that the battery powers.

Get another car and cable

Get another vehicle that has a healthy battery, since you’ll be charging your battery with theirs.

You also need a pair of jumper cables.

Connect the cables

You will note that the cables consist of one red cable and one black cable, both with clamps at the end of them.

It would be best if you connected the red clamp on the positive terminal of both batteries, and the black cable on the negative terminal of both batteries.

The positive terminal is identified with a (+) sign, and the negative terminal is identified with a (-) sign.

Start the other car

Once the cables are connected, start the car with the healthy battery. 

After this, you need to let the car run for about 4-5 minutes.

This will help charge your dead battery with the sufficient energy it needs to get your car going.

Start your car

Once the wait is over, try starting your car. 

Hopefully, the battery should have enough juice in it to give the alternator the necessary voltage. 

If the car doesn’t start, wait another 4-5 minutes then try again.

Get help

If your cars started by now, you need to go see a mechanic as soon as possible. 

The car won’t run very long, and the strain placed on the battery and actuator will actually be very harmful in the long run.

Since there is only a limited amount of time before the car shuts down again, make sure to avoid any roads that have high-speed traffic, and stick to roads with slow and low amounts of traffic.

A helpful tip would be to make sure that once the car is started, all accessories that may use electricity are turned off. 

Turn off the headlights unless it’s absolutely necessary, or if it’s nighttime.

Shut the A/C, and the radio or music player if it’s running.

The reason behind this is that the actuator handles most of the electricity supply, whereas the battery is there for supplying power to the actuator in order to get it started and to supply power to the electronic accessories when the actuator is off.

When the battery is used as a power source instead of the actuator, you’ll barely get any time out of it before it shuts down.

If you’re getting a friend to help you, you might need to stop and jumpstart your car every 2 minutes, since it might be shutting off that quickly.

Final thoughts

Well, we hope that you were able to understand the symptoms and temporary solution to getting yur car started with a bad alternator. 

We hope that your car troubles are over soon!

Zach Reed

Hi, I'm the founder of! Having owned a wide variety of vehicles in my life, I was astounded at how hard it can be to find answers to common automotive questions. Rather than sit idly, I decided to create this website to help others!