Car symptom
Battery / charging warning light
The charging light means the alternator is not keeping the battery full. Test the voltage before it leaves you stranded.
Most likely causes
- Worn alternator / regulator
- Slipping or glazed belt
- Bad earth / connections
- Ageing battery
- Overcharging
Checks to run
- Measure charging voltage (13.8-14.6 V)
- Check belt tension and condition
- Clean terminals and earths
Tools you may need
Multimeter
Battery tester
Confirm before replacing. These are hypotheses to check — never buy parts on a guess. If the fault involves brakes, airbags or fuel under pressure, use a professional.
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FAQ
It depends on the cause. Some causes are cheap and quick; others (like a head gasket or seized caliper) need attention soon. Work through the checks in order and confirm before replacing parts.
Start with the free checks listed here. If they involve high voltage, fuel under pressure, airbags or brakes, let a professional handle it.
The interactive diagnostic asks targeted questions to narrow it down, and every cause must be confirmed with a measurement — never guess.