Joined: Mar 2018 Posts: 694 Threads: 33
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Location: Lot region FRANCE
The curious case of the glimmering ignition light. Over the last couple of months or so, the ignition light had started to glimmer even when the dynamo was charging well. It was the same wether on 1/2 or full charge. I put it down to a dynamo problem, but the other day, the cutout was sluggish to 'pull in' . I cleaned the cutout contact faces by sliding some paper back and forth between the contacts, leaving a dirty trace on the paper.
Hey presto, cutout working as it should and no glimmering ign light. - Happy boy again.
Joined: Jan 2019 Posts: 1,567 Threads: 20
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Location: Bala North Wales
Car type: 1933 RP Standard Saloon
A glimmering ignition light is a sure sign of a cutout problem. As you have discovered, it is usually caused by excessive resistance at the cutout points, so, instead of shorting the ignition lamp completely, the dynamo tries to charge through the lamp.
Joined: Aug 2017 Posts: 2,748 Threads: 31
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Location: Auckland, NZ
The contact points are soft silver and use o fabarasive papers likely to embed material. A clean finger nail file can be used for (very conservative) retouching (battery disconnected). A poor ign switch connection will also cause the lamp to glimmer at normal speeds. Often evident as warm switch/key.