Guide to Jump Starting A Car
Jump-starting a car is never at the top of anyone’s daily to-do list. You walk out to your car, get in and give the key a turn. Nothing happens, or you hear that all familiar click, click, click.
Whether it is a brand new car that you just bought or a vehicle that you have maintained for years, walking out to a dead car battery is something that will make you want to start the car buying process all over again.
You may have jumper cables but are not sure how to jump-start a car or have never tried jump-starting a vehicle before.
Even if you are not sure how to attach jumper cables this procedure is easy to follow.
However, the good news is you can still get your car back up and running, with a few simple steps we will show you how to jump a car battery correctly.
When jumping a car battery, you want to use caution and follow these steps carefully to avoid damage to your vehicle or personal injury.
Before we dig into the process for jump-starting a car, we highly recommend that you read and review our used car buying guide along with the new car buying guide to help avoid any urgent needs such as this in the future.
Preparation: Jump-Starting A Car
Jump starting a car isn’t rocket science; however, there is some care involved. Correctly lining up the vehicles involved and making sure everything is attached correctly will ensure a safe, smooth jump start process.
How To Jump A Car Battery: Using Jumper Cables to Start a Car.
- Place the vehicles so the batteries are as close as possible. Also, be sure to set the parking breaks. Make sure both cars are in the park position, are not touching, and the engine is off. That should be pretty easy for at least one of the vehicles.
- Turn off all additional powered items in both vehicles, including headlights, blinkers, radios, air conditioners, etcetera. Also, unplug any accessories from the cigarette lighters or power sockets in either car.
- Locate the positive (+) and negative (-) terminals of each car battery. If you have any trouble, look for a (+) and a (-) marked on the plastic top of the battery next to the posts.
- This may be hidden under the battery cable leads. Positive posts commonly have red wires attached to them, so this will help you find the positive post. Knowing the positive battery post from the negative battery post side is the most important step in jump-starting your car correctly. This will allow you to safely jump the vehicle without damaging the battery or alternator.
Negative Ground Posts
- If the battery is cracked, and liquid is leaking out or if the dead battery is hot or has a sulfur smell DO NOT proceed. Take the battery to be tested to see if it is chargeable.
- If you do find a cracked battery, stop, buy a new battery and swap the replacement battery with the cracked one. If you try to jump-start a cracked battery, it could explode.
- Clean any corrosion off of the dead battery terminals (The fuzzy greenish deposits that form on battery posts). We recommend using safety glasses while working over the top of a car battery.
- You may be able just to wipe it off, or you may have to get battery post cleaning brush or sandpaper. If you have tools, loosen the wires from the posts, clean them, and re-tighten the wires to the clean posts. If you have a battery post brush on hand, wipe the battery posts until they are shiny. If your tools are limited, use sandpaper or pinch pliers to clamp down on and scrape off the corrosion.
- Examine the battery jumper cables. Typically, the positive battery cable jump leads are red or orange, and the negative or ground cable is black. However, always check to be sure.
Connecting and Using Jumper Cables To Jump Start a Car Battery
Once you’ve prepped the batteries, it is time to connect the jumper cables.
Knowing how to jump a car safely includes wearing eye protection in case the battery bursts.
Use caution when connecting the cables and never let any of the clamps loose ends touch each other or any part of the car during the process.
Spread out the battery cable clamps on the ground until you are ready to connect that end of the cable to the booster car. Letting the ends touch the car, grill, hood or any other metal surface could produce a short that will damage that surface.
Jump Starting A Car: How to Hook-Up Jumper Cables
- Begin by connecting one end of the positive cable (Red Clamp) to the positive post on the dead battery.
- Connect the other end of the positive cable (Red Clamp) to the positive post of the good battery or “working car.” (Note in this picture, the battery is a side post battery, commonly used in GM vehicles and newer cars.)
- Next, connect one end of the negative cable (the black clamp) to the negative terminal post of the good battery. Some of the newer cars are difficult to get to the battery post so use caution not to touch any metal parts when installing the jumper clamps to the live battery.
- Connect the other end of the negative cable (the last black clamp) to a solid, shiny, unpainted metal part of the engine on the dead car.
A good place to connect this is on a bolt or clean metal surfaces on the engine block. Avoid putting the negative cable directly on the dead battery to reduce the chance for a spark to explode a leaking battery.
As a last resort, attach the negative cable to the (-) post on the dead battery. NEVER connect the ground cable to the car body which includes fenders, hood, front grill or radiator mounts, or you may damage the vehicles electrical system or any of the many computers the car has.
Only connect the ground clamps to the (-) battery post or the engine itself as shown here.
Getting Your Car Started
Once you’ve gone through the process of preparing the batteries and connecting the cables, you’re now ready for the moment of truth. It’s time for jump starting your car.
Begin by again making sure that the headlights of both cars are off to allow the maximum amount of power to reach the dead battery.
The car with the good battery should be started first.
- Let the car run for several minutes before trying to start the dead car. This will allow the jumper cables to charge your dead battery. Hold t gas down slightly to speed up the engine idle but don’t race the motor. If the automobile that is running has a tachometer (A gauge that tells the RPM of the engine), a fast idle is about 2000 RPM. This allows power to be charged up with the bad battery before cranking the dead car. It is a good sign you connected everything correctly if your vehicle’s dome light comes on or gets brighter.
- After you have waited for a time to charge the bad battery, shut the car doors and try to start the other vehicle. If it sounds like the motor is attempting to crank but won’t turn over completely or makes a rapid clicking noise, turn the ignition off and wait a few more minutes. Trying to jump a car with an insufficient charge or weak battery could damage the starter motor and overheat the jumper cables.
- Rev, the engine of the good car a little bit but don’t race the motor. A car’s charging system will be putting out its maximum charge at a long, fast idle. You may also want to move the cables around slightly on the battery posts to make sure you have a good connection at the clamps. They may spark a bit, but that is OK but be careful because they can get hot.
- Most cars electrical system runs off of 12 to 14 volts so it is not as dangerous as you may think. The voltage is not high enough to hurt you; otherwise, the battery posts would be concealed where you could not touch them. However, when jump starting a car, the cables and clamps can get hot so car owners should use caution in handling them.
- Once your car has “charged” for a few more minutes, try jump starting the battery again. If it starts, it is your lucky day, but leave the car running for a few minutes to make sure it gets successfully restored. If your car did not start, don’t give up hope yet. Check out the troubleshooting section below to see how to jump a car battery if it still won’t start.
Removing the Jumper Cables
Once you have successfully restarted your dead car, you can remove the jumper cables in reverse order. Remember the wires can get hot so use caution when handling them.
After jump starting a car battery, let it run while you disconnect the jumper cables. You want to be careful to remove them in the reverse order in which you connected them.
Also, avoid letting the clamps touch one another or any part of the vehicle during removal. This will prevent damage to the vehicles surface and electrical system.
- First, Disconnect the negative cable from the engine block from the car that was previously dead.
- Next, Disconnect the other end of the negative cable from the negative post of the good battery.
- Then, Disconnect the positive cable from the positive post of the good battery.
- Finally, Disconnect the other end of the positive cable from the positive post of the dead battery.
Try to Restart Your Car
Even if you have successfully restarted your dead car, you do not want to shut it off for fifteen to twenty minutes. The car’s alternator puts power back into the battery slowly.
The battery will not be fully charged until it has about 500 amps stored in it. This could take over an hour for a full charge.
After you have let your jump-started car run, or you have driven your car for a minimum of twenty minutes.
Turn off the engine and see if it will restart on its own without any cables.
This is a good test to make sure the charging system is working. It is also a good indicator that you will not get stranded on your way home.
If the engine does not crank on its own, you’ll be jump starting your car again, and you may want a buddy to follow you to your next location. Additionally, If your car won’t start again on its own. This is a good sign that something is actually wrong with the battery. Also, the charging system and should be checked by your mechanic.
If This is a Car That You Are Thinking of Buying
If this is a car you have been leasing or one being sold by a dealer or individual that you may want to buy, have the seller replace the battery if it is shot.
Get it in writing that the car had a dead battery when you first looked at it, and the dealer agreed to fix it at no charge and make him warranty that repair in writing.
If you just bought the car, especially if this is a rent to own car, report this to the dealer as soon as possible to avoid potential car dealer scams. Many dealers need to jump a car that has sat for a long time.
Also, the battery can be damaged from sitting at low voltage.
When buying a new or used car, many electrical parts can be damaged from dead batteries or salesmen that don’t know how to jump a car correctly.
How To Jump A Car - Troubleshooting Tips
If you have recently purchased a car, and you have computer problems, starter motor or alternator failure, battery failure or any electrical related issues. Report this to the car dealer, or you could be a victim car buying scams.
One indicator of a car that has a history of battery problems is to check the battery posts and cables. If it has many scratches on them from jumper cables.
The car has had been dead many times and needs to be fixed before you close your new car purchase. Alternatively, if you already bought the car, you may want to review our “After The Sale” guide.
How to Jump a Car - Troubleshooting Tips
If you attempted to jump start your vehicle with the typical jump, start routine, and it did not crank, there still may be a few things you can do.
In fact, it could just mean that the dead battery is not getting enough voltage from the good battery due to bad cables or a bad connection.
Add these troubleshooting tips to your growing knowledge of how to jump start a car safely.
- Try adjusting the cables to make sure you are getting a stable connection. Don’t worry if you see a few sparks. That is normal.
- Try disconnecting the negative cable from the dead cars engine block and moving the negative clamp to the ground post (-) of the dead battery.
- Try different cables. If you are using old jumper cables, it could just be that the cables are bad. This is a common problem with wires that are eight gauge or higher. The place inside the handle where the cable is clamped to the handle gets loose or corroded.
- Make sure that all electronics in the car are off. Also, remember to close the door, so that your dome light is not on when trying to crank the engine.
- Remove any corrosion or rust that you may have missed initially. Even if you have to use a nail file, do it to scrape off the corrosion until the lead posts are clean.
- If you see any smoke from the battery terminals or if the terminals get hot. This heat is also a sign of a bad connection and needs cleaning. In this case, you may need to remove the car’s battery cables to clean them correctly. Do not try to continue to crank the engine if the battery posts are smoking or you can damage the battery.
In most cases, you can revive a dead battery by jump-starting a car or use the troubleshooting tips to get it going again. If all else fails, call a tow or AAA to get on your way.
In any event, you may also want to stop by your local auto parts store to have a quick diagnostic test run on your car battery for free.
Do not buy a new battery unless there is a problem with the old one and don’t be scammed by the guy selling the batteries.
All batteries that are not fully charged will fail a battery test.
Even good batteries that have not had enough time to charge will fail so make sure they have plenty of time to recharge before testing.
A proper battery test should be done after the battery is fully charged to a minimum of 12 volts. If it will not charge, this means that the battery is bad.
Final Thoughts
Many people have purchased a new battery only to find out that the alternator in the car was the actual problem.
If you are thinking of replacing this car with a new car or trading it in for a new car, then you will need to know how to get a fair offer for your vehicle.
Have any problems fixed first, or you may lose thousands of the trade-in value of your investment.
Sometimes a poorly starting car is due to a hundred-dollar battery.
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Now you know how to jump start your car if the battery goes dead. It is a good idea to keep a good set of jumper cables in the trunk for other emergencies.