Symptoms Of Bad Battery Cables [How to Fix?]

Are you facing issues in starting your car? The most common problem would probably be an improperly functioning car battery or a bad alternator. During the cold winter nights, when you try to jumpstart your car, and it’s not working, the battery would be in good condition, but the battery cables might be the culprit. 

The car batteries produce an electrical charge generated when the chemical energy turns into electrical energy. This charge provides adequate power to start your car. If you happen to have bad battery cables, you need to look out for loose connectors, loose wire connections, or corrosion around the terminal posts. If such symptoms persist, it’s time to get new battery cables. 

Through this post, we will find out in detail about everything you need to know about bad battery cables and how you can fix them. 

Bad Battery Cables:

If you happen to own a car, you know how valuable car batteries are for starting the car without any hiccups. But not many are aware of the role of car battery cables. Let’s find out the symptoms of bad battery cables: causes and how to fix it. 

What Are Car Battery Cables?

Car battery cables are cords that provide the electric current from the automobile’s battery to the electrical system around the car. As most batteries consist of insulated and heavy-duty wires, they carry huge current loads with lesser challenges. 

Battery cables contain two heavy-gauge wires, which include the positive and negative wires. The positive car battery cable is sealed in a red encasing and connected to the vehicle’s computer. On the other hand, the negative battery cable, otherwise known as ground cable or ground strap, has a black encasing and is connected to the car’s chassis for grounding. Together, these cables make a closed-loop to produce continuous power flow. 

Before disconnecting the battery for servicing, make sure to remove the negative battery cables first. This step is very important as it prevents all sorts of damages to the wiring and short circuits that tend to occur. If the bad battery cables are causing a lot of problems for your vehicle’s electrical system, here are some symptoms you need to look out for. 

Causes of a Defective or Bad Battery Cable

Car electrical problems mean you’re stuck and won’t be able to go anywhere. Here are some symptoms that indicate your battery cables are failing and you need to replace them. 

1. Your vehicle won’t start:

To start the car, the battery cables must be attached to the automobile’s frame and the car starter. With time, the battery cables tend to get corroded, disconnected, or frayed, creating problems when starting the engine.

In case your car doesn’t start automatically or takes longer than usual to start, this indicates there is a problem with the battery. The cables provide low power, and the engine finds it difficult to start; you can try wiggling the battery cable to start the car. Bad battery cables affect the proper flow of current needed to start the engine. 

2. Low voltage battery:

Low voltage battery is another issue that arises due to defective battery cables. If the positive car battery cable is damaged, the alternator won’t get fully charged, resulting in less power than normal. It is advisable to use a digital multimeter and check the battery’s voltage to make sure there is any change in the voltage that comes from the battery terminals.

The normal car battery voltage must be about 12.6 V when the car is switched off. While the car is running, the voltage must be between13.7 to 14.7 V. If the voltage reading is different, you either have a bad alternator or a defective positive battery cable. 

3. Dim Headlights:

If you notice flickering or dimming headlights, the reason might be bad negative battery cables that are damaged or frayed. Headlights need the full power of electricity and must be firmly connected to the car battery to illuminate and clearly see the road in front of you. The poor battery terminal connection due to corrosion is the reason why your lights flicker or get dim while driving. 

4. Complete system shutdown:

If your car does not receive any electrical power, it can impact the entire vehicle components that need electricity for its functioning. If nothing happens when you turn on the engine, it indicates the electrical system is dead, and no power is provided to the engine. In case the cables are corroded or cut off to the point where there is no connection with the battery, then your car’s electrical system will completely shut down. 

A closer examination of the battery cables will enable you to find out the exact problem. In most cases, it might be a simple issue, but for some, you must address the issue by replacing the entire battery cable.

5. Hot Battery Cables:

Battery cable corrosion will increase the flow of electricity or resistance through the wires, resulting in the generation of heat. Suppose the negative battery cable is hot to touch after turning off the car or while the vehicle is running. In that case, there is a good probability that the resistance of the negative battery cable is very high, causing it to heat up quickly. The best option to resolve this problem is to replace the negative battery wires. 

How To Check For The Bad Battery Cables?

While getting close to the battery cables for inspection, keep metallic items away from the car battery to avoid electrical hazards. By following all the safety precautions, you can check the cables for problems or possible damages in the following manner.

  • Pull the cables from the battery post and check if there is any sparking between the alternator post and the battery post. This indicates there is a loose connection or corrosion near the cables.
  • Check the battery terminal connection of the positive cable to find if they’re in good working condition and there is no corrosion or dirt around the ends—proper connection results in a good current flow from the battery to the engine starter. 
  • If you happen to notice any white or greenish deposits near the battery terminals or other metallic parts, make sure to wipe it clean to avoid corroding the entire battery and affecting the overall function.
  • Carefully examine the negative car battery cable, check if it is connected properly to the car’s chassis, and wipe the area clean of all deposits.

How To Fix Defective Battery Cables?

Bad battery cables can stall you from starting the car normally. Avoid attempting to repair a corroded or broken battery cable. The best way to fix a defective battery cable is to replace it with new ones from the terminal end. Here are the steps you need to follow, but before that, you need to get a screwdriver, ratchet, wrench, and socket ready.

  1. Remove the bad battery cables from the terminal post using a wrench or screwdriver. While removing the battery cables, make sure to remove the negative cable first to avoid short circuits or shock accidents. 
  2. Slide the new wire through the copper conductor and solder the negative to the chassis ground and the positive end to the fuse block tightly. Before placing the new battery cable, compare the voltage output at the car battery terminal posts to determine if they are of the same thickness.
  3. Keep the disconnecting wire short to avoid interference with the trunk or hood alignment while opening. Lastly, tighten up the lead just securely to the connection posts.

If you’re experiencing bad battery cable issues and not sure how to fix them, you can always get help from a professional to handle the replacement. This will increase the overall efficiency of your vehicle and prevent any further issues down the lane.

Liam Dare

As CEO of, my passion for the automotive world motivates me to build online businesses that provide information and entertainment to users. I am proud to contribute in a positive way to the automotive community.