Car won't start and just clicks: battery, starter, or something else?

You turn the key or press the button and hear a click, or a fast chatter of clicks, but the engine doesn't turn over. That sound is useful: it usually means the car is trying to start, but the starter isn't turning the engine.

What is the click?

Our explanation, not from a cited source: the starter has a heavy-duty switch, the solenoid, often switched in turn by a relay. The click is that switch closing. Once it closes, it connects the battery to the starter motor, which draws a very large current. If the battery or the wiring can't supply that current, the motor doesn't turn, and all you hear is the switch.

What the pattern usually suggests. This table is our own reading of how the circuit works, not taken from a manufacturer's service information, and it hasn't yet been reviewed by a mechanic. Use it to decide what to test first, not as a diagnosis:

Two rows have some support in the sources we cite. For slow cranking, Varta describes the "tired groaning sound" of a poorly charged battery and explains why cold makes it worse (below). For the last two rows, General Motors' owner's manual for the 2025 Equinox is a good reminder of the simple causes: the shift lever has to be in Park or Neutral to start, and "If the engine does not start and the security light stays on, there is a problem with the system." A weak remote key battery can also stop a push-button car from starting; the Equinox manual's backup is to place the key in the center console and try again.

Why is the battery usually the problem?

Because a poorly charged battery is the usual cause. Varta, the battery brand made by Clarios, says the reason for starting difficulties "is usually that the battery is poorly charged" (Varta). Cold makes it worse. Varta explains that the battery's chemical reactions slow down in the cold, and that below 0 °C (32 °F) engine oil becomes "highly viscous", so the starter needs more current just as the battery can deliver less. See why car batteries die in cold weather.

Working lights are not proof of a good battery. Clarios' head of development puts it plainly: "Nothing is more annoying than a battery that is still strong enough to turn on the lights, but too weak to spin the starter" (Varta).

Step 1: What does the battery's voltage tell you?

It tells you more than the sound does: put a digital multimeter across the battery posts. East Penn Manufacturing's battery care guide gives these resting voltages for a flooded 12 V battery: 12.6 V is fully charged, 12.4 V about 75%, 12.2 V about 50%, 12.0 V about 25% and 11.8 V flat. AGM batteries read a little higher; the battery voltage chart has both columns.

• Well below 12.4 V: the battery is low. Charge it or jump-start the car, then find out why it went flat.
• About 12.6 V or more, and it still only clicks: the battery has charge, so look at the connections next. A battery can still be weak under load; East Penn calls a load test on a fully charged battery "the best way to determine if the battery is delivering adequate electrical performance."

Step 2: Could it be the connections?

Yes: a loose or corroded cable can stop a car as surely as a flat battery. East Penn's visual inspection list includes "Loose cable connections", corrosion and damaged terminals. One General Motors bulletin, for no-start and stalling complaints on 2014–2020 full-size trucks and SUVs, lists as possible causes battery cables with "high resistance and/or loose connections", a poor ground, a shorted battery cable at the starter solenoid, or "a discharged or faulty battery" (GM 18-NA-161). The same bulletin is one of the sources for our article on U0100, lost communication with the engine computer.

Safety first. East Penn's rules: wear safety glasses, because "All batteries generate explosive hydrogen gas"; keep sparks and flames away; never lean directly over a battery; and when you take cables off, disconnect the grounded (negative) cable first and connect it last. Clean corrosion with a baking soda and water paste, then rinse.

Step 3: How long should you wait between attempts?

Wait at least 15 seconds, GM's Equinox manual says, and stop after a few tries: repeated attempts won't fix a low battery and can do harm. The manual warns that cranking "for long periods of time, by trying to start the engine immediately after cranking has ended, can overheat and damage the cranking motor, and drain the battery. Wait at least 15 seconds between each try." Other manufacturers give their own limits, so check your manual. If a few attempts don't do it, stop and diagnose.

How do you jump-start a car safely?

Start with your owner's manual, then follow the sequence below. Some cars have remote jump-start terminals instead of easy-to-reach battery posts (the 2025 Equinox's positive terminal is under a trim cover), and East Penn says to check the manual for this before you begin. East Penn also says that if you are unsure you can do it safely, don't attempt it and call a professional. GM warns that pushing or pulling the car to start it "will not work" and could damage it. Never jump-start a battery that may be frozen. East Penn warns it can explode; remove it and charge it once it has warmed to room temperature.

East Penn's sequence, with GM's checks added:

1. Use only a donor with a 12 V, negative-ground system (GM). Park the cars so they don't touch, set the parking brake, and switch both off. Turn off lights and accessories in both cars (GM). Keep hands, clothing and tools away from the engine fan, which GM warns can start even with the engine off.
2. Check the cables: GM says not to use cables with loose or missing insulation.
3. Red clamp to the positive (+) terminal of the dead car.
4. Other red clamp to the positive (+) terminal of the donor.
5. Black clamp to the negative (−) terminal of the donor.
6. Last black clamp to the dead car's engine block or frame, or to the remote negative terminal or grounding point its manual shows, never to the dead battery's negative post.
7. Start the donor. East Penn says let it run at least 30 seconds; GM's manual says idle it for at least four minutes. Follow the longer figure if your manual doesn't say.
8. Start the dead car, then remove the cables in exactly the reverse order. GM says to let the car idle for several minutes afterwards.

GM adds: "If it will not start after a few tries, it probably needs service." Use a flashlight, never a match, near the battery.

If the jump works, why did the battery go flat?

The jump shows the battery was low. Find out why it keeps dying, or it will happen again:

• It sat too long, or has a drain. See how long a car can sit before the battery dies and parasitic battery drain.
• Short trips. Varta says that if a car is used infrequently or only for short distances, "the alternator cannot fully charge the battery." Driving after a jump helps only partly; see how long you need to drive to recharge a car battery.
• It's worn out. Fully charge it and have it load-tested. East Penn notes you can't load test a discharged battery.

What if it still clicks with a good battery and clean connections?

The fault is then more likely in the starter, its solenoid or relay, the cable to the starter, or the engine itself (our inference). That's a job for a shop. Don't tap on the starter or bridge its terminals yourself: it's under the car, close to hot and moving parts.