7 Signs Your Alternator Is Failing

The alternator keeps your battery charged and powers your car’s electrics while the engine runs. When it starts to fail, the symptoms can be confusing — and they’re often blamed on the battery instead. Here are the signs to watch for.

1. The battery warning light

The dashboard light shaped like a battery isn’t only about the battery — it usually means the charging system. If it glows while driving, the alternator may not be charging properly.

2. Dim or flickering headlights

If your lights dim at idle and brighten when you rev the engine, the alternator may be struggling to keep up with demand.

3. A battery that keeps going flat

A healthy alternator keeps the battery topped up. If you’ve replaced the battery and it still goes flat, the alternator is a prime suspect.

4. Electrical gremlins

Slow power windows, a flickering dashboard, or audio that cuts out can all point to inconsistent voltage from a failing alternator.

5. Strange noises

A whining or grinding noise from the engine bay can be worn alternator bearings.

6. A burning smell

The alternator belt or internal windings overheating can produce a faint burning-rubber or hot-electrical smell.

7. Stalling or hard starting

If the alternator can’t supply enough power, the car may be hard to start or even stall.

How it’s tested

Diagnosing a charging fault means measuring the alternator’s output voltage and current under load, checking the drive belt, and testing the battery at the same time. We do all three so you don’t replace a perfectly good battery when the alternator is the real problem. Book a charging-system test at our Randwick workshop if any of these sound familiar.