What are the signs of a failing battery?

A failing battery typically exhibits specific signs that indicate it is losing its ability to hold a charge or function properly. Difficulty starting the engine is a classic symptom of a battery issue; the engine may crank slowly or not at all, indicating insufficient power. Dimming lights, particularly when starting the vehicle or while idling, suggest that the battery is not supplying enough voltage to keep the electrical system operating optimally.

These signs are directly related to the battery's primary function of providing voltage to the starter motor and other electrical components. When the battery begins to fail, its voltage output decreases, leading to struggles in starting and reduced brightness of lights.

In contrast, fluctuating tire pressure, excessive fuel consumption, and increased engine noise are symptoms associated with other vehicle issues, such as problems with tires, fuel system inefficiencies, or mechanical engine issues, respectively. Therefore, the combination of difficulty starting the engine and dimming lights specifically points to battery failure.