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MG MGB Technical - no alternator red light on dash

I have a 1970 MGB. Recently the light for the alternator on the dash went out. The head lights went dim and then the next day my car would not start. I replaced the alternator and the battery, both new, because they checked out bad. The car starts but the generator light, which is red on the dash, when I turn on the ignition will not glow red at all. Any sugestions, I'm afraid I'll just burn the alternator and battery out again.

Thanks - Gary
Gary

Hi Gary.

Assuming that the new alternator is good, I can only assume that either the warning light bulb has blown or there is a wiring fault.. I would check the bulb first.

Don
Don

Hi,
Reach up behind the dash and replace the bulb, it is burned out and the alternator will not charge properly until this circut is complete. When the key is turned to ON the light should glow brightly and "excite the diodes" which will cause the alt to charge. No light on dash - no excited diodes - no charge in battery - no go anywhere... I replaced an alternator and battery years ago ( and I knew that the red light had not been working for a few weeks prior to replacing these items) soon I was at the same point.. no charge - no start. I replaced the burned out bulb and everything has been working fine ever since. The old alternator was still good after all, which I now have as a spare.

Alan
Alan

Just a thought, but there are three or so clips in the plug that goes in the alternator. Sometimes one is dirty/no making connection. I'd check this too. One is for the red light I think. Also, take a voltmeter and check the battery. Should be 12V with car off, and about 14 or so volts running.
J Arthurs

This thread was discussed on 01/02/2003

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