At 05:28 PM 7/9/98 -0600, you wrote:
>Thanks for the reply!
>Yeah, I've got a volt meter and an ohm meter (multimeter actually). I've
>done a cursory check of the connections and haven't found anything. For
>further info, I did take the alternator to Checker to get it tested and it
>does appear to be working. Perhapse the PO did something weird with the
>wiring? There are two attachments going to the alternator. One is a large
>block that attaches to a trio of blades. There is a fat brown/yellow wire
>attaching to the leftmost blade of this trio (looking foreward). There is
>also a thin brown/yellow wire attaching to the rightmost blade (IND). The
>middle blade has nothing attached to it. The second attachment is just a
>single blade toward the bottom of the alternator. There is a white/yellow
>(i think) wire and a pink wire attached to this. These wires seem to go to
>ground, but internally I don't think anything in the alternator is hooked up
>to this blade.
>>
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I got the impression from you original post that the system was working,
then quit. Is this correct?
When did the system quit charging?
======
General proceedure.
Check voltage at the battery with engine off.
Start engine. Rev to about 2000.
check voltage at the large brown/yellow wire connected to the alternator,
also check voltage at the battery.
With the engine off, and the battery charged, you should get a reaidng of
about 14 volts.
Then when the engine is running and reving, you should get a reading of
OVER 14 volts at the alternator and about .2 less at the battery.
Alternators have the main current coils on the frame. The "field" is the
rotating bit in the center. When there is a need for more current, the
regulator cauese a higher current in this field and as such a greater
current is created in the stator windings, connected to the diode pack that
recitifies the current to DC for the battery/system.
If the alternator test good on a test rig at the store, then there is
likely a problem with the connections in the car.
You can test the resistance of the large brown/yellor wire (discommected at
the alternator), from the alternator end to the positive terminal of the
battery. It should be less than .1 ohm. That is less than one tenth ohm.
If all that is correct. Messure the voltage at the small alternator wire
while running the engine up and down. (head lights on), you should see an
increase in voltage as the RPM go up. Again this should be OK since the
alternator test OK on the bench.
There is one more thing. The indicator lamp on the dash is realy connected
between the battery and the alternator. When the alternator is not
charging current is allowed to go from the battery to ground through the
alternator. As the alternator is charging this DIFFERANCE in potential is
low so there is not light on the lamp.
You indicated that this lamp is behaving in this way. So you (as verified
by bench test) have an alternator that is producing voltage (and current).
So be very careful testing that harness, and check those voltages. Yous
should find the trouble.
Let us know.
Thomas Howard
'72 GT6, (and a good bit of USA Iron)
Lakeside Union School District
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