* Starter Motor Issues: The single click is the sound of the solenoid within the starter motor engaging. This solenoid is an electromagnet that activates the starter's gear to engage the engine's flywheel. If the click is the *only* sound, the solenoid may be working, but the starter motor itself is likely faulty (worn brushes, a seized gear, or internal failure).
* Circuit Problems: The click could also mean the circuit delivering power to the starter motor is broken or has a very high resistance. This could be due to:
* Corroded battery terminals or cables: Clean and tighten these connections first. Corrosion dramatically increases resistance and prevents sufficient current from reaching the starter.
* Faulty starter cable: A broken or severely corroded cable anywhere between the battery and the starter will prevent the starter from receiving enough current to crank.
* Faulty ignition switch: The ignition switch might not be sending the necessary power to the starter solenoid.
* Faulty solenoid: While the click *suggests* the solenoid is working, it's possible it's weak and not delivering enough power to crank the motor. This is less likely if it's a consistently single click and not a rapid clicking or no sound at all.
* Bad connection at the starter motor: The connection between the positive cable and the starter motor itself could be faulty.
Troubleshooting Steps:
1. Check Battery Terminals and Cables: This is the easiest and most common fix. Clean them thoroughly with a wire brush and baking soda solution, then reconnect securely.
2. Check Starter Cable: Visually inspect the cables leading from the battery to the starter. Look for any damage, corrosion, or loose connections.
3. Have the Starter Motor Tested: This usually requires professional help. A mechanic can test the starter motor to determine if it's functioning correctly.
4. Check the Ignition Switch: This is more difficult to diagnose without experience. A mechanic can test this component and determine if it's the source of the problem.
In short: A single click with a fully charged battery strongly suggests a problem with the starter motor or its electrical pathway. Don't attempt extensive electrical work yourself unless you have experience. It's safer and often more efficient to get it checked by a qualified mechanic.
