The click you hear is the starter solenoid engaging, but not having enough power to crank the engine. Here's why that's probably the case and what to check:
* Low Battery Voltage (Despite new battery): Even a new battery can be bad out of the box. Have the battery's voltage tested with a multimeter. It should read around 12.6 volts when not under load.
* Bad Battery Cables: Check the battery terminals and cables for corrosion, looseness, or damage. Clean them thoroughly and make sure they're securely connected. A loose connection creates high resistance and prevents sufficient current from reaching the starter.
* Bad Starter Solenoid: This is the most likely culprit. The click indicates the solenoid is getting power but is failing to engage the starter motor. It's a relatively inexpensive part to replace.
* Bad Starter Motor: If the solenoid seems fine, the starter motor itself could be failing. It needs significant current to turn the engine.
* Poor Connections: Check all connections related to the starting system, including the ground cable (very important). A bad ground can prevent the flow of current.
Why it's unlikely to be the alternator or voltage regulator: These components only come into play *after* the engine starts. They charge the battery. If they were faulty, your car would likely have starting problems eventually (due to a dead battery) but a single click points to a different issue in the immediate starting circuit.
Troubleshooting steps:
1. Battery Voltage Test: This is the first thing you should do.
2. Cable Inspection and Cleaning: Clean and tighten all battery terminals and connections.
3. Solenoid Test (if possible): This often requires some electrical knowledge and tools, but you can try tapping the solenoid gently with a hammer (use caution) while someone turns the key – this sometimes temporarily resolves the issue, further indicating a problem with the solenoid.
4. Starter Motor Test (requires more expertise): This might involve testing the starter's windings or having a professional diagnose it.
In short: Get your battery tested first. If it's good, focus on the starter solenoid and battery connections as the most likely problems. Don't jump to the alternator and voltage regulator until you've ruled out the other, more probable causes.
