Once again, I need the TECH'ies to come out of the wood work....
On my 1973 BGT, my alternator light has been popping on, sometimes
bright, sometimes dim. Revving the engine will turn it off briefly,....
sometimes!
I Checked the WHT ckt. connections, (which is the return side of the
ignition idiot light ) things look fine. I then added a dash mounted
Voltmeter across the WHT ckt. to GND and using a clamp on Amp Meter on the
PLUS battery cable (at the battery) I could then monitor the charging
system.
The Volt Meter easily rises to +14 - 14.5 volts, when the car is
first started from it's initial 12 volts. While the light is off, the Amp
Meter will show a charge rate or roughly 3 - 5 amps. When the battery gets
to 14 volts, ( a minute or two) the light comes on, and I'll see no current
flow on the amp meter. Gunning the engine will occasionally turn off the
ignition light at first, but after a few minutes it will just stay on.
Watching the Volt Meter, I can see a rhythmic pulsing of the voltage.
It's only a 1/2 a volt or so drop, but is rhythmic and doesn't seem to be
related to engine RPM. I'm assuming this pulse is the Fuel pump being
energized.
Conditions: Starts quick and easily. All ace. turned on, only drops the
voltage a max. of 1 volt. (with the idiot light on or off)
QUESTION #1: Do I suspect the battery, alternator, or something on the WHT
ckt. that is loading down the line.
QUESTION #2: If it's the alternator, would it be the brushes? regulator?,
diode array?
QUESTION #3: Could the battery being at 14.5+ volts, make the alternator
think it's not charging, so the light comes on, since the alternator output
voltage is the same as the battery voltage?
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