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MOTRS

MGA

1955-1962 / Roadster / Coupe / United Kingdom

Common Electrical (Lucas)

Dynamo Undercharging

Symptoms

The charge warning light stays on or flickers. Battery goes flat. Headlights dim at idle.

Cause

Worn brushes, a dirty commutator, or a failed voltage regulator. The dynamo's output is limited, approximately 22 amps, and marginal for cars with upgraded lighting or accessories.

Fix

Rebuild the dynamo ($200-$400) or convert to an alternator in a dynamo-style housing ($400-$600). The alternator conversion is the better long-term solution.

Cost mentioned in fix
$200-$400$400-$600

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