What does the alternator do?
The alternator generates electrical power while the engine is running and helps keep the vehicle battery charged.
It also supplies electrical power for many of the vehicle's electrical systems.
Common symptoms of alternator problems
- Battery or charging warning light
- Repeatedly weak or discharged battery
- Dim or fluctuating lights
- Electrical accessories behaving strangely
- Engine stalling after electrical power drops
- Unusual noise from the alternator area
Do not replace the battery without testing the charging system
A failed alternator can repeatedly discharge a good battery. Replacing the battery without identifying the charging problem may only provide a temporary solution.
A proper diagnosis should include charging-voltage testing and inspection of the alternator, belt, wiring, grounds, and related components.