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Starting a car with a pair of jumper cables is one of the quickest ways. But it is not a guaranteed remedy as many factors come into play while jump-starting a car. But if your car won’t start with a jump cable, you can take measures to make it happen.

Mostly, it occurs due to completely dead batteries, faulty accessories, damaged battery terminals, faulty jumper cables, alternators, or ignition switches. It can also happen due to an empty gas tank.

But don’t worry. Here, we will go through each cause individually in detail and also tell you how you can fix them. You will also learn some tips so you can avoid such a frustrating problem in the future. So, Let’s Start!

Possible Reasons Car Won’t Start With Jumper Cables Connected

There are many possible scenarios that can restrict your car’s battery from starting even if you connect jumper cables. However, eight of those most common cases are listed below:

Dead Battery

The battery functions as the heart of a vehicle. Every component of the car engine gets power from it to run the car smoothly on the roads. However, a faulty battery is one of the crucial causes of a car’s inability to jump-start.

Like most products, car batteries also expire. Your driving span and environmental factors can affect the condition of your car battery. Therefore, replacing it with a newer one every three years is better.

But what if you have replaced your car battery recently, and now it isn’t starting?

A major reason for a car battery not to start with a jump might be a short circuit or a faulty cell inside it. In this instance, investing in another new battery is a perfect solution. However, you must get your completely dead battery checked first.

Battery Terminals

The quality of your battery connections is crucial to the operation of a jump start. The corroded terminal connections restrict the flow of electric charge from the donor battery. As a result, the jump start becomes unsuccessful.

Your car won’t start with a jump if the terminal posts are broken or aren’t securely attached to the battery. In such circumstances, you must examine the battery terminals and connectors for signs of corrosion.

Fortunately, this issue is simple to resolve. You can remove the corrosion by using baking soda and water. Prepare a sufficient amount of the solution and scrub off the corrosion with the help of a brush dipped in the mix.

Once you remove the corrosion, try to jump-start your vehicle again by reconnecting jumper cables with the battery.

Bad Jumper Cables

Checking the condition of your jumper cables is essential. Sometimes the reason behind the failure of a jump start is the low-quality jumper cables. These cannot handle the high electric flow and can get easily damaged. Also, smaller jumper cables are unable to carry enough electric charge.

If the cables are in your garage or the back seat for a long time, check if they are broken or not. Any damage to the clamps or wire can lead to a short circuit as well. So, you better be careful with your apparatus.

Investing in jumper cables is an intelligent choice, as cheap jumper cables can cost you more in the future. Also, keep the jumper cables attached to the battery for around 5 minutes before trying to start the engine. That’s how you can effectively charge a bad battery. 

The jumper cables can fail to work over time. Therefore, you should keep replacing them frequently with a different set of cables. Also, a portable jump starter can help you drive your car smoothly on the roads for a longer time. 

Faulty Alternator

A vehicle’s battery can’t cover all its electrical needs. The alternator recharges the car’s battery after starting it. An alternator powers the vehicle’s electrical system when the engine starts working.

Jump starting requires a good alternator. A bad alternator can cause dead batteries as it drains them, reducing its capacity and starting power. Thus, your battery may be undercharged and sulfate if your alternator is weak or malfunctioning.

A faulty alternator may not result in this issue right away. Yet, it can lead to your car shutting down soon after you remove the jumper cables. Hence, before shelling out cash for a new battery, you must differentiate between a failing battery and a malfunctioning alternator.

You can test it out by attaching a multimeter with the battery (discussed below). If it shows current passing, most probably, your alternator is faulty.

Moreover, if your battery won’t jump and it’s less than three years old, check your car’s alternator. Have a qualified mechanic check out the alternator if there are any warning signs.

Clogged Fuel Filter

Fuel filters play a critical role in a car engine. All cars have fuel filters that clean fuel before it reaches the engine. This process causes these filters to clog with particles, and clean fuel cannot get to the engine. Without fuel, the car won’t start. Thus, even with a decent battery and alternator, you cannot turn on your vehicle immediately.

You must replace your fuel filter to keep it clean and working over time. Most automakers suggest replacing the gasoline filter every 20,000 to 50,000 miles. Yet, many mechanics disagree and recommend replacing or cleaning it every 10,000 miles. Hence, for further details, you can consult your owner’s manual.

Faulty Ignition Switch

Where do you start a car from? Yes, the ignition. So, what if all the other components are fine and this car’s electrical system is the one that is causing the problem? It can be a major problem, as you can easily mistake it for other issues and waste time in their repair.

It is located behind the car’s steering column, close to the ignition lock cylinder. Both components must be in place for your vehicle to turn on. Some damage can happen while using an ignition switch during a period. Therefore, a faulty switch can be the main problem if your car battery is in good condition. 

You can only jump-start your car with a working ignition switch. If your car key fails to turn on your vehicle after a few tries, consider checking out the switch for a while. Also, if your dashboard lights flicker while driving, you must check it to locate the problem.

Turning on the headlights can help pinpoint the problem. If the dashboard and headlights start working, but the engine doesn’t turn on, the ignition switch may malfunction. Hence, if you discover any of these clues, call a mechanic to get it fixed.

Bad Neutral or Clutch Safety Switch

A safety switch is another essential part of a vehicle. It prevents a car with an automatic transmission function not to start unless in a park (P) or neutral (N).

Yet, if you have a manual transmission car, you must firmly depress the clutch pedal before starting it. 

Your car will start getting incorrect readings if a safety switch breaks. Hence, it might lead to a no-start situation for the engine. Thus, there is no way to jump-start the car.

You can check out whether it kicks off by shifting into Neutral. This indicator makes it easier to tell if the neutral safety switch has been damaged.

Empty Gas Tank

When a car doesn’t start even after the jump start, the most typical cause is an empty tank. Even if your car has a good battery, spark plugs, and an alternator, the fuel must be in the tank.

No fuel means no lubrication for the gas pump, so running your car on an empty tank is not a good idea. The engine may suck in the air along with the remaining fuel traces. It can contaminate the gas tank.

The engine might not restart if this air enters it, as it disrupts the ideal air-fuel ratio required for combustion. Make sure you have at least a quarter full gas tank before you start your journey to avoid potentially hazardous situations. Therefore, you must make it a routine to check if there’s enough gas in the tank before leaving your place. 

Check Out When Your Car Won’t Jumpstart:

Car Won’t Start Even With a Jump: Troubleshooting Steps

Replace the Battery

To ensure the car functions effectively, the battery must give electricity to all components. Therefore, it makes sense that you cannot jump start a dead car battery in the first place. Thus, replace your battery at least once every three years to ensure it can hold a charge and perform properly.

Check Jumper Cables/Connections

It is crucial to ensure that your jumper cables are always in good working order. Jumper cables, either too light or too long, need to be more durable to hold and carry enough electricity. Moreover, poor-quality cables might also prevent a jump start from working as these tend to break easily. 

Check Your Battery With a Multimeter

A multimeter is a simple tool for determining the battery’s charge level in a vehicle. You can directly connect the multimeter’s leads to the battery’s positive and negative terminals. A faulty battery could cause a voltage reading lower than 12.6 volts.

Start the engine and check for a voltage reading greater than 10 after making any necessary adjustments. While driving, if the voltage in your car dips below 5, it is faulty and needs to be replaced.

Seek Help from a Roadside Assistance Company

In the case of a car breakdown, roadside assistance is a lifesaver. If your vehicle stops working and leaves you stuck, this emergency road service can assist you in getting back on the road again.

The help desk team offers over-the-phone solutions to problems when customers contact for assistance. However, if they determine that you require more specific repairs, they will dispatch a tow truck. It will transport your automobile to the closest auto repair facility.


How do You Tell if a Battery is Completely Dead?

Several warning signs indicate that your car battery is completely dead. These include a slower start, working headlights but no start, constantly flashing car lights or a swollen battery. You can also discover that your car battery is dead if your vehicle starts and then dies on the spot. 

Why Won’t My Car Start but has Power?

Typically, there can be multiple reasons behind a car that won’t starting. Thus, the most common causes are a dead battery, a broken starter, a faulty alternator, or corroded connecting cables. Moreover, if the engine properly maintains compression and your car has a functional fuel system, but it still won’t start, this can lead to malfunctioning spark plugs.

How Long Should I Drive After Jumping My Car?

You must ensure that your vehicle runs for at least half an hour once it gets a jump start. Instead of letting it sit and idling, you should leave for a long drive to get desirable results.

That’s how your battery can get a full charge and won’t give out on you again. Hence, you might need another attempt at the jump start if it does not run for at least 30 minutes right after receiving a jump. 

Does Reviving Engine Help Jump Battery?

In a nutshell, yes! However, this only works if the battery is already completely discharged before you start revving the engine. However, if your battery is not charged sufficiently, there is no use in continuing.

Which Fuse Will Keep a Car from Starting?

Any of the big main power distribution fuses should do the work. These include the fuel pump fuse, ignition fuse, ECM fuse, relay fuse, or whatever counterparts your vehicle has. Furthermore, check the owner’s manual to learn about fuse rating if the number is not printed directly next to the fuse holder.

Final Consideration

Starting a dead battery with a jump cable is one of the most convenient ways. However, the problem arises when it won’t even start with the process. Here you have learned 8 reasons why a car won’t start with a jumper cable and how you can fix the issue in 4 easy ways.

You can check the cables are connected properly to the battery terminals and that they are not faulty ones. You can also check the battery or replace it if it is all dead. But the final option will be to seek roadside assistance. Follow these steps to make your car’s engine roar again and begin your journey.

Agustin is part of the team at Road Speed Solutions, a reliable and efficient roadside assistance business with over a decade of experience in New Jersey.

What sets Road Speed Solution apart is the team's commitment to giving back to the community, regularly donating to local charities and supporting small businesses. Choose Roadside Speed Solutions for prompt, trustworthy roadside assistance services.