Quick answer
A single, loud click when you turn the key (with no engine cranking) usually points to the starter motor or its solenoid — the starter gear is not engaging the flywheel. It can also mean a poor connection at the battery or starter, or a fully discharged battery that has enough power to click but not to crank.
Common causes
- A failed starter solenoid that clicks but does not extend the starter gear
- Corroded or loose battery terminals limiting current to the starter
- A worn or dead starter motor with worn brushes or a failed Bendix drive
- A deeply discharged battery that cannot deliver cranking amps
How to diagnose it
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Check the battery and terminals
Clean any corrosion from the battery posts and tighten the cable clamps. Test battery voltage with a meter — a healthy battery reads above 12.4 V at rest.
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Tap the starter while a helper turns the key
Lightly tap the starter body with a wrench while someone turns the key. If the engine cranks, the starter has a dead spot and needs replacement.
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Test voltage at the starter
With a helper turning the key, measure voltage at the starter's main terminal. Battery voltage present but no cranking confirms a starter failure.
When to see a mechanic
- The battery and terminals are good but the starter still only clicks
- The starter is difficult to reach or requires lifting the vehicle
- Multiple electrical systems are dead, suggesting a bigger wiring fault
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