72 Vette - Meter read
Thread Starter
Instructor
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72 Vette - Meter read
On 72 Vette, when conducting voltmeter testing of entire circuitry, is the correct reading for the circuitry always "0"? Or, is there always juice running thru that will show 12 volts on meter.
I've not found any shorts or anything that would show 12 volts still going thru the system.
Dougtov
I've not found any shorts or anything that would show 12 volts still going thru the system.
Dougtov
Le Mans Master
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What exactly are you looking for? IF you pull a battery cable off, and test between that cable and the battery, IF there is something on, you will see 12 volts. If nothing is on, you will see 0.
Le Mans Master
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There are a lot of videos on you tube that explain in detail how to read, use and understand what a volt ohm meter is telling you. Well worth the time to watch some.
Team Owner
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Are you talking about the center console gauge? If so on an '72 it's an amp meter not a volt meter. When the charging system is running right an ammeter should show close to zero most of the time depending on the electrical load on the system.
You'll notice right after starting your engine, which puts the highest current draw the system will see, your ammeter will be almost all the way to the +40 shortly after the engine fires. After a few minutes when the alternator "tops off" the battery after starting you'll see the needle slowly go back to the middle zero mark.
If you are using a DMM put the + lead on the output of the alternator and the - lead to ground. Your alternator should be putting out 13.5 to 14.5 volts. You can also check this at the battery, again put your + lead on the + terminal of the battery and the - lead on the - terminal. You should see the same voltage (may be slightly lower because of wire resistance but it should be within 1/2 volt).
You'll notice right after starting your engine, which puts the highest current draw the system will see, your ammeter will be almost all the way to the +40 shortly after the engine fires. After a few minutes when the alternator "tops off" the battery after starting you'll see the needle slowly go back to the middle zero mark.
If you are using a DMM put the + lead on the output of the alternator and the - lead to ground. Your alternator should be putting out 13.5 to 14.5 volts. You can also check this at the battery, again put your + lead on the + terminal of the battery and the - lead on the - terminal. You should see the same voltage (may be slightly lower because of wire resistance but it should be within 1/2 volt).
Last edited by theandies; Aug 7, 2017 at 04:36 AM.
Thread Starter
Instructor
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Thank you for your help.
I was referring to the test meter I'm using to find a drain in the system, which I found last night. It appears the alternator is the culprit. Not original to this car. Now need to find a 72 Alternator 1100544 , 621 amps--know of anyone who might have one?
Dougtov
I was referring to the test meter I'm using to find a drain in the system, which I found last night. It appears the alternator is the culprit. Not original to this car. Now need to find a 72 Alternator 1100544 , 621 amps--know of anyone who might have one?
Dougtov
Le Mans Master
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Dougtov - I'm not one to discourage folks from learning new things, but some of your statements are not understandable. The 621 amps statement for instance. It might be worth your time to get some assistance before you start replacing parts.
Thread Starter
Instructor
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I have fat fingers-- It should have read 61 Amps.
Thanks for your input.
Dougtov
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You can put new guts in your existing alternator. New bridge, diode trio, regulator, brush holder, rotor and stator, front and rear bearings. Use your case and nobody will ever know but you. Odds are you won't need anything but the brush holder and regulator. All of the diode stuff is an easy test with a meter.
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Has the altenators.
Marshal
Has the altenators.
Marshal
