My thanks to PD and MJ, and RF for help with the battery..
That means a new or reconditioned alternator? Is there a good argument for
replacing the battery first or is there any other alt test that would
confirm the problem?
thx for the help
Personally I would try a different battery first just to see what
happens. Of course I have a couple of extra batteries sitting here,
so that would be easy to test...
It really is tough to say without having the car... Reinspect
everything for any visual evidence, like a cable that looks poorly
connected or dirty etc. Also re-examine the fuse box. Try pulling and
reseating all the fuses, or even better replace them all...
Good Luck, and let us know what it really turns out to be... We aren't
psychic really (at least I'm not).
A good, fully charged battery should have at least 12v, usually around
12.5v. A good alternator should give about 14.5v at idle. So just take
a multimeter to measure on the battery posts.
Most modern cars have an integrated design and a bad battery will cause
wrong reading from alternator output. So start from the battery.
Don't forget to check wiring, especially at the connections. If in
doubt, loose the connection, sand them clean before putting back. I
once worked on a Chevrolet that died completely while on the road. It
had no cranking, no lights, not even emergency flasher! A few minutes
later, everything came back normal. It took me a few weeks, and a few
complete deaths, until I found the culprit. On that car, the positive
cable goes to the starter and everything else connects there. Even
though the nut was very tight and looked clean, there was enough
corrosion to kill the car.
Is the diode the light itself that comes on or is it somewhere else in a
In the first case, I assume that the panel with the lights pulls out and
then I can get at the
diode - soldered in or plugged in or?
Hope these questions aren't too "ignorant" or is it "iggerent" ;-)
there are 6 diodes in an alienator
3+ AND 3 - when working properly the current goes one way through them.
if one opens it may feed to ground
there on the alt itself.
the diodes convert AC voltage to DC.
beats the old generators.
there are diode pacts but i have never my self replaced one
some one here has though i am sure
the case, minus a few cans!
Thanks poolman for the diode info. I doubt I'll need to get that far into
the electronics but I may need to.
Today I had my first real look.
1 Rotated the fuses and used two spares to replace two that looked
In the next few days I'll buy a complete set, just in case.
2 Measured the battery voltage with engine off - 12.75v
3 Measured the battery voltage with engine idling - 14.1v
4 The battery terminals look clean and have no corrosion
5 Removed the alternator cable. It has a 3-slot plug that fits on 3
prongs on the unit
and is held there with a spring clip - no corrosion.
Tomorrow I'll probably be able to make a battery substitution, just for the
test, or possibly
a few days, if the light does go out.
Thanks all for the help :-)
PS the light is still on :-(
This is embarrassing. Originally my friend told me about this battery light
and I did the inquiring for her. Finally, someone else was riding with her
in the car when she mentioned the problem. He had a close look at the light
and the symbol near it. It did look like a square and somewhat like a
battery, but had some other squiggle on it. Finally he decided it wasn't the
battery light. When he checked, it was the cooling water light. Dumped in
some water and the light was gone. Oh dear, what idiots!
Sorry about the wild goose chase.
That light actually only indicates the overflow is low, so it really
is no threat to the engine temperature (at that point). Still it's nice
to know what the warning light means :~)
Glad to hear the mystery is solved...
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