If your car’s starter motor clicks and the engine won’t turn over, this could be due to a number of things. The most common cause of clicking when starting the car is a low battery. Most people would assume the starter is bad if it just clicks, but low voltage can cause the starter to make this sound.
The battery is the heart of the starting and electrical system. If the battery has died or has a weak cell, this can cause the starter to just click. Many times the battery could die due to a door being left slightly ajar, causing the dome light to stay on. Other times, a vanity light or phone charger may be left on. During my time as a master auto technician, a trusted co-worker locked me in the trunk to make sure the trunk light went off when the trunk was closed.
To test the battery it must have a good charge. If the battery is not fully charged, the tester will indicate that it needs to be charged before the test can continue. The first step in checking the starter motor and electrical system is to make sure the battery is in good condition. Most auto parts stores will check batteries for free. Once the battery is determined to be good, the rest of the system can be checked. Loose or corroded connections can also cause a click and the car won’t start.
Start
The starter solenoid on many Ford vehicles is on the inner fender, on most other vehicles the starter solenoid will be mounted to the starter. The click you hear many times is the solenoid. But low voltage from a dead battery, a bad battery, or poor connections can cause this. Most of the time, if the vehicle can be started, the starter motor is fine. This would also indicate that the connections to the starter motor are good.
Alternator
Once the vehicle is running, the alternator output can be checked. If the alternator is not charging the battery, it will run out during the process of starting the car and driving. When checking the alternator, the voltage and amperage output can be measured. The diode pattern will also be checked to make sure the alternator does not drain the battery when the engine is turned off. In the past, DIYers could disconnect the battery while the vehicle was running to check the alternator, if the car kept running, the alternator was good. Doing this in computerized vehicles can be harmful. If the battery is disconnected while a computerized vehicle is running, the alternator output can rise sharply, allowing the excess voltage to boost the computer.
Drums
When purchasing a replacement battery, the cold cranking amps required for the vehicle should be verified. It is best to buy a battery with more cold cranking amps than the minimum required. Also, when buying a battery, you should consider whether you want it to be maintenance-free or not. If the battery is difficult to access or has a cover, a maintenance-free battery is preferred. For example, on some Chrysler Sebrings and Chevrolet Corvettes, the battery is located behind an inner fender and on a Chevrolet SSR. the battery is located under the box where the spare tire would normally go. If you install the battery yourself, be sure to note which side is positive and negative in case you were sold the wrong battery.
terminals
Terminals must be free of corrosion and must be tightened securely. Sometimes, especially on import vehicles, the battery terminals will be very thin and may have hairline cracks causing a poor connection. Avoid forcing the battery terminals by hitting them. The battery case may be damaged and cause a leak; if battery acid leaks out, it can lead to rapid corrosion. If the battery terminal bolts do not tighten, it is recommended that the terminals be replaced. When the connections are tight, you should not be able to twist them by hand.