Battery Charge Light
Discussion
Hi. My battery charge light is on just very dim . It is the same on tick over or with revs. It is no brighter with lights on . Car has an original alternator that was reconditioned and has only done about 4K . I have checked connections on alternator and battery, checked and cleaned 100amp fuse. I have checked alternator it is showing 13.5 amps flickering off and on at 14.5 amps. I don’t have a clue about electrics and can’t think of anything else to check. Any help Thanks.
Have you removed and physically checked the 100A fuse mounted on the chassis? I had this problem in my car and the fuse turned out to be cracked, not completely broken, so the battery wasn't charging correctly.
It's the type shown at the top of this thread and inside a black plastic cover usually, although many owners replace with a stronger 'midi' fuse:
https://www.pistonheads.com/gassing/topic.asp?t=11...
There are other threads on here, and photos somewhere too.
I presume you mean 13.5 to 14.5 volts, not amps.
It's the type shown at the top of this thread and inside a black plastic cover usually, although many owners replace with a stronger 'midi' fuse:
https://www.pistonheads.com/gassing/topic.asp?t=11...
There are other threads on here, and photos somewhere too.
I presume you mean 13.5 to 14.5 volts, not amps.
As said the 100A fuse failure mode is not to blow but to fracture ( who thought mounting it on the engie was a good idea) so the only way to be sure is to remove it,
For now your next test is with engine off check battery voltage then check voltage at the alternator they should be near enough the same.
Steve
For now your next test is with engine off check battery voltage then check voltage at the alternator they should be near enough the same.
Steve
dc400 said:
Hi.Sorry volts not amps ..I didn’t remove the 100amp fuse just wiped it clean and tightened the little nuts holding in . I can remove it and look for a fracture and order a new one as suggested .I have just checked battery and it is getting 13.5 volts is that about right.
Your description - "faintly glowing charge light" was exactly the same as my experience. Voltage testing as you've done does not rule out the fuse. It was the 100A fuse. It was only when I got under the car and undid both the clamping nuts did the hairline fracture become apparent (it dropped into 2 pieces). I replaced mine with a 100A 'midi-fuse' which is more mechanically robust than the strip type. Midi fuses are easily obtained from your local motor factor/auto electrical shop.
Nick
If negative supply is good and positive supply is good, don't rule out a volt-drop along the ignition supply to the warning light or a volt-drop along the alternator to warning light cable
What I mean to say is don't do what the idiots do and bang a new alternator on before being sure that the warning light circuit is good
What I mean to say is don't do what the idiots do and bang a new alternator on before being sure that the warning light circuit is good
Plan B said:
................ I’ve forgotten how the red light operates so I suppose I’m guessing in the dark and trusting in god on this one!
When you turn on the ignition +12volt goes to one side of the charge lamp. The other side connects to the alternator which, whilst not running, provides a path to earth (battery negative). When the alternator is charging it applies +12volt to that same wire so now the charge lamp has +12volt on both sides so does not light.The lamp will glow if the voltage on one side of the lamp is higher than the other..
As has been said I think you have a charging issue if you are seening 15volt at the battery.
Steve
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