headlights dim at idle?

Dimming that follows engine speed points at charging or earth problems, not the bulbs.

Is it safe to drive with this?

Short local trips are usually fine, but the fault will get worse and often damages other parts if you leave it.

The most likely repair is alternator replacement, which runs $265–$1,310 in the US including labour, or $150–$650 in parts if you fit it yourself.

Dim at idle, bright when revved.

Poor buffering makes lights pulse.

Halogens lose output badly after 3 years.

headlights dim at idle?: Dimming that follows engine speed points at charging or earth problems, not the bulbs.
Is it safe to drive with this?: Short local trips are usually fine, but the fault will get worse and often damages other parts if you leave it.
How much does it cost to fix?: The most likely repair is alternator replacement, which runs $265–$1,310 in the US including labour, or $150–$650 in parts if you fit it yourself.

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Batteries, alternators, starters, sensors and wiring

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