Ignition Light

[DeeRo]

Any suggestions, please, as to why my ignition light does not go out as the engine fires up? The light actually increases in brightness with the engine revs. The car has not been run for a few weeks and I can't remember this being the case before. New distributor, coil, HT leads and battery fitted. No alterations made to the wiring layout on the back of the speedo. Thanks

[Bill_qaz]

Which light do you mean, red means not charging, amber means no oil pressure. Some cars also have a blocked oil filter warning light. More info required to point you in the right direction

[DeeRo]

Hello Bill, Thanks for your swift reply. It's the red ignition light. Can't see that there is a charging problem. The car always starts first time and teh battery has been on the car for more than six months.

[myoldjalopy]

Might be overcharging - is it a dynamo or alternator?

[Bill_qaz]

Assuming its a dynamo
Or do you have an alternator?
Do you have a multimeter you can test voltages?
If so first easy test is check the battery voltage static circa 12v then start engine and rev it up and battery voltage should be over 13v to show its charging.
If you don't have a multimeter a crude test is to put headlights on full beam at engine idle and when you rev up you should see them brighten. To show its charging

[Andmurph]

I had similar issues with a Hillman Imp recently. Fitted with a dynamo. The ignition light came on with the ignition and got brighter as the engine res increased. The issue was a faulty diode in the rectifier. The alternator was sent away for repair and is working perfectly now.

[DeeRo]

Thanks for your interest All and, yes, the car is fitted with a dynamo. Will check output next time I'm in the garage!

[Bill_qaz]

https://share.google/N22KcH6OJrmvcP4AU

You may find this article useful

[DeeRo]

Thanks Bill, By the look of things I need to do the following:
Check that the dynamo is actually charging;
Fit the new wiring loom, which I have already purchased as a spring project;
Check the regulator in accordance with your video clip.
Really appreciate everyone's help on this matter.

[geoberni]

When the system is working and the light is off, it is because the lamp has essentially 12v from the battery to one side of it and 12 from the dynamo to the other. Therefore no voltage difference across it.
See this Lucas booklet. Intended for the small garage owner with limited electrical knowledge. Really easy to follow.
https://www.mg-cars.org.uk/imgytr/pdf/lucas.pdf