Symptoms of a Bad Battery Cable

The battery cables connect the battery to the vehicle’s electrical system, and keep it grounded.

The positive cable, which is usually red, attaches to the positive battery terminal at one end. At the other end, it usually connects to the starter solenoid, as well as various other points in the electrical system, depending on the car.

The negative cable, which is usually black, connects to the negative terminal at one end and a grounding point at the other.

Both cables fasten to the battery with dedicated terminals. The cables are large in order to meet the demands of the electrical system.  

Signs of a failing battery cable  

A faulty battery cable can cause a number of problems. Some of the most common include:

• Car won’t start: Cables that are broken or severely damaged can prevent power from reaching the starter, resulting in an engine that won’t crank.
• No electrical power: Bad cables may isolate the battery from the vehicle’s electrical system, preventing the lights and accessories from working.
• Engine cranks slowly: Damaged or corroded cables create excessive electrical resistance in the starter circuit. As a result, power flow to the starter is reduced and the engine cranks slower than usual.
• Warning lights are on: Modern cars are loaded with sensitive electronics. Damaged or corroded battery cables can prevent the electrical system from getting the proper voltage supply, resulting in a myriad of warning lights on the dash. 
• Drivability problems: A bad battery cable can throw off a vehicle’s onboard electronic control system, causing a wide range of drivability problems. For instance, a bad ground cable may cause a vehicle to stall intermittently or lose power.

» MORE: Get an estimate for a battery cable replacement

How to fix the problem

In many cases, it may be possible to affix a new terminal to the cable. But if the cable itself is corroded or damaged, it should be replaced; not repaired. 

On some vehicles, this is a relatively simple job that a handy DIYer can tackle as long as they take the necessary safety precautions (always disconnect the negative cable first). But on other cars, the cables snake everywhere, making replacement difficult. When in doubt, leave the repair to a professional.