Hi all, my altanator is not charging, have tracked it down to the altanator not creating the earth for the charge light circuit. How do i fix it from here from here??? Cheers, James

The charge light circuit is only earthed when the alternator is not creating any charge current.

It's nowt to do with the actual charge itself, it's just an indication.

Sorta like the temperature gauge is not the cause of the overheating, it's just the messenger of death.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

my charge light isnt on at all. if i unplug the small brown and yellow wire from the altenator and earth it the light comes on. Mmm, i puzzled!!!

Could the rectifier be stuffed??

Lol. The Brown/yellow is the charge wire. It's the line the alternator charge travels down to charge your battery.

You have however proven your alternator is so far successfully producing current!
The charge light is a negative logic. If it is extinguished - then all is dandy, if it is on - then there is a fault. It comes on at startup because the engine is not spinning enough to produce any charge. Once the alternator voltage rises above the battery voltage after startup, it will extinguish the light.

Now what is the rest of the problem. The battery isn't providing enough power to start the car? What is the voltage across the battery terminals (after a good external charge overnight), and what is the voltage when the car is running? Does it rise from the steady battery voltage?

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.