Battery terminal ends serve the simple but important purpose of connecting the battery cables (and the vehicle's entire electrical system) to the battery. They are usually made of lead or another highly conductive metal that is heavy duty in nature but still offers low electrical resistance.

Since they are the first point of contact between the battery and the vehicle’s electrical system, if the battery terminals have any problems, this can affect the entire vehicle and should be serviced to restore functionality. When battery terminals do begin to fail, they will usually produce a few symptoms that can notify the driver of a potential problem.

1. Problems starting the vehicle

Difficulty starting the vehicle is one of the first symptoms of a problem with the battery terminals. If any corrosion develops along the battery terminals, this may interfere with the connection and the vehicle may have trouble starting. This can be caused by corroded or even loose battery terminals. The vehicle may experience difficulty starting, slow cranking, or rapid clicking when the key is turned.

2. Corrosion on the battery

One of the most common symptoms of a battery terminal issue is visible corrosion. Since the terminals are in direct contact with the battery they are exposed to the acidic fumes from the battery acid and as a result are prone to developing corrosion. Corrosion can interfere with the battery terminals ability to conduct power and in severe cases can even completely block the flow. A careful inspection for any signs of powdery white or blue corrosion anywhere on the terminal or along the cable can reveal if there is a problem.

3. Loss of electrical power

Another common symptom of a bad battery terminal is loss of electrical power. This usually occurs when a terminal is severely corroded or has broken. A severely corroded or damaged terminal that does not make good electrical contact may cause total loss of power. Terminals corroded to this degree will usually require replacement.

While they are a very simple and inexpensive component, battery terminals do play a very important role in the overall functionality of the vehicle’s electrical system. For this reason, if you suspect that the terminal ends may be having an issue, or are showing any signs of corrosion, have a professional technician, such as one from YourMechanic inspect your battery to determine if you require a terminal ends replacement, or if another repair is more appropriate.

This article originally appeared on as Symptoms of Bad or Failing Battery Terminal Ends and was authored by Ed Ruelas.

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