A car's starter is one of its more important engine components. It is a small electric motor that engages the engine when the driver turns the key. Once the engine begins to run, the starter disengages. A bad starter is just one possible reason an engine won't start, but there are symptoms that can help pinpoint a problem with a starter.
One of the most common symptoms of a bad starter is a clicking noise when turning the key to the "on" position. The clicking comes from under the bonnet and should be clearly audible since the engine won't even begin to turn over. If the engine does begin to turn over but never starts or if there are multiple clicks until the driver releases the key, the starter is actually functioning and the problem is elsewhere.
Headlights that are dim before trying to start the engine indicate a bad battery and the starter might be fine. However, when the lights shine at full brightness but become very dim when the driver turns the ignition key, the starter is almost certainly the problem. In this situation, the alternator is sending electricity to the starter, reducing that available for the lights. Even with the boost, the starter is unable to start the engine.
Smoke coming from under the bonnet can also indicate a faulty starter. This can occur when the starter motor burns out. If possible, open the bonnet and try to pinpoint the source. It may be possible to see smoke coming from the starter, which is in a metal cylinder mounted on the engine. Even once smoke clears, the starter may have a burnt smell.
A faulty starter can cause battery terminals or wires to heat up. Like the dim headlight symptom, this comes from the alternator trying to send extra electricity to the starter. Always exercise care when handling battery terminals. If they cool down after the driver releases the key, the likelihood of a starter problem increases.