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Old 22nd September 2020, 11:51   #1
squire
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Red face Charge light

Alternator failure at 167k so I bought another alternator and my garage fitted today. Now here's the slight problem, although the new alternator is charging healthily at 13- 14 volts both on the IPK and by multi meter across the battery terminals the charge light doesn't go out it just dims? With ignition on it's bright with engine running it just dims, doesn't completely go out.

Anyone have any ideas what might be the cause, all wiring has been checked and connections are clean.

Martyn
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Old 22nd September 2020, 11:58   #2
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Hi Martyn
I always thought healthy was over 14 v? Ideally 14.3-14.7? Sub 14 may be the problem

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Old 22nd September 2020, 14:35   #3
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Hi Martyn
I always thought healthy was over 14 v? Ideally 14.3-14.7? Sub 14 may be the problem

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Exactly Scott, just can't understand why the charge light still faintly glows
I wonder if it's because the new alternator has a bigger amperage than the old one?
See you later.

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Old 22nd September 2020, 14:48   #4
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May be check with Jamie tonight but i don't think the charge light is a direct connection from the alternator i think its triggered by the engine ecu

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Old 22nd September 2020, 14:52   #5
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Charge voltage should ideally be 14-14.4 from memory, does the light go out when revs are applied and the voltage creeps up?
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Old 22nd September 2020, 15:30   #6
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Charge voltage should ideally be 14-14.4 from memory, does the light go out when revs are applied and the voltage creeps up?
Thanks for your response, the charging is fine around 14v even 13.7v with all extras on rear screen, lights, blower etc but the charge still glows, intensity of it doesn't change.
I'm not unduly worried about it as the charging system is working ok but it bugs me lol

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Old 22nd September 2020, 15:34   #7
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I always thought healthy was over 14 v? Ideally 14.3-14.7?
Hi Scott,

The charging voltage can be anywhere between 13.0 and a maximum of 14.5 volts. 14.7 v would definitely be too high.

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Old 22nd September 2020, 15:48   #8
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I'm not unduly worried about it as the charging system is working ok ...
Hi Martyn,

I appreciate that your voltage measurements conflict with the state of the charging warning lamp but there must be something wrong because the warning lamp should not glow, not even dimly.

I see on the diesel that the alternator's battery connection goes via the starter motor. It might be worth checking that. Perhaps you have a faulty regulator inside your alternator. Was it brand new or second-hand?

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Old 22nd September 2020, 16:27   #9
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Hi Martyn,

I appreciate that your voltage measurements conflict with the state of the charging warning lamp but there must be something wrong because the warning lamp should not glow, not even dimly.

I see on the diesel that the alternator's battery connection goes via the starter motor. It might be worth checking that. Perhaps you have a faulty regulator inside your alternator. Was it brand new or second-hand?

Simon
Hi Simon,

The alternator was brand new, not even a refurbished one, and there is obviously a "gremlin" somewhere, I intend to get the old one refurbished at some stage but will go to where I will be taking it to see if they have any ideas. I'll also get on T4 when I can and see what that throws up. The car starts on the button and goes very well, so in my opinion it's got to be a silly thing which are always the hardest to find.

Martyn
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Old 22nd September 2020, 20:44   #10
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Follow the loom back from the alternator and check for any damage - not unknown for cables to rub through as they pass under the slam panel.
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