Alternator not charging/ignition light not on

[Vic Butler]

Thanks Charles.
A simple test would be to disconnect the alternator plug, earth the small ignition light connection and see if the light works then.

[Charles Farran]

Hi Vic,
Exactly what i suggested in my post at 6.43pm on Saturday!
Cheers
Charles

[Vic Butler]

Sorry Charles, must have missed it.Reread and found it.

[GeoffK]

I’ve got it!! I have seen the light- literally!!
There is no earth for the ignition light as the route to earth within the alternator has been broken, therefore it will never light up. Never thought of that! Also as the alternator is faulty and not producing either charge for the battery nor the 12v required for the brown/yellow wire the light will never light up via that route.
It would seem that there were 2 faults within the alternator. The new one is ready to be fitted so that should cure both problems.

Thanks again for all your support and advice
Cheers Geoff

[Vic Butler]

Let us know the results.

[Charles Farran]

Glad you have had a "light bulb" moment!
Cheers,
Charles

[GeoffK]

My last post on this thread.
New alternator fitted
Ignition light going on and off as it should
14.3 volts at battery terminals at 2000 rpm
Such a relief that everything is working properly
Again, thanks for your help
Cheers
Geoff

[JontheHutt]

Hi, complete Newbie here.

I am also having trouble with my alternator/no battery charge. I've read through this post as well as other places online and not sure if my problem is the same or not...as to be honest I struggled with some of the technical stuff....(give me a hammer and I'm fine )

I have recently inherited a '78 rubber bumper B from a family member. Up until recently it was running and charging just fine and then one day the alternator warning light came on, I tried replacing the brushes etc but no joy, so ended up fitting a new alternator. and still the light is on.

Unfortunately after double checking with a multi meter the battery still doesn't seem to be charging. I had to change the plug as part of the process to fit the new alternator, and I think I've wired this correctly. (the thick brown wire in the middle, the brown/yellow wire on the "small" connection)

I'm wondering what to try next, a thread I read somewhere suggested the engine needs a rev to "excite it" and someone I know suggested a voltage regulator? Would this help at all? I think the car could probably do with a complete rewire at some point but I'd like to put that off for a while yet.

Thanks in advance.

[Vic Butler]

Check the small brown/yellow wire connection at the alternator plug. It's wired correctly with the thick brown wire in either of the large terminals and the brown/yellow wire in the small terminal.
If ok check the continuity to the ignition light and if that's ok run the engine at about 2,000 rpm and connect a multimeter set to volts across the battery terminals. The reading should be about 14 volts.
The ignition light excites the alternator when the engine is started and when the voltage from the alternator gets to 12v the light goes out.

[JontheHutt]

Hi Vic,

Thanks for the tip, will give it a try at the next opportunity and let you know how I get on.

Jon.