Car clicks but won't start

Symptoms

• Rapid clicking from under the hood or dash
• Dashboard lights dim or flicker
• Engine does not crank or turn over
• Radio and lights may still work

Likely causes

• CommonWeak or dead 12V batteryMost common cause; batteries lose the ability to deliver high current before they lose the ability to power lights.
• CommonCorroded or loose battery terminalsA poor connection can mimic a dead battery even if it tests fine on a charger.
• PossibleFailing starter motor or solenoidThe solenoid can click without engaging the starter gear.
• PossibleBad ground strap or corroded cableA weak ground can starve the starter of current.
• Less commonAlternator not charging properlyA battery that never gets recharged will act dead even if new.

What to do

1. Turn on the headlights; if they are very dim or go out when you try to start, suspect the battery.
2. Pop the hood and check both battery terminals for looseness, white/blue corrosion, or a cable that spins when wiggled.
3. If terminals look clean and tight, try jump-starting the car from another vehicle or a portable jump pack.
4. If it starts after a jump but dies again soon, the battery likely can't hold a charge and needs replacement.
5. If it still won't start after a good jump, the clicking may be the starter solenoid rather than the battery.
6. Have the battery and charging system load-tested at an auto parts store or shop; most do this for free.
7. Clean corroded terminals with a wire brush and a baking-soda-and-water solution once the battery is disconnected.
8. If the battery tests good and connections are clean, have the starter and starter relay tested.

Tools and parts

• Jumper cables or jump box
• Wire brush
• Wrench for terminal clamps

When to call a pro

If cleaning terminals and a proper jump-start don't fix it, see a mechanic or auto electrical shop to test the starter and charging system.

Safety