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j.obfuscation
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| Posted: Jan 23 2011 at 7:26pm | IP Logged
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I've got a recently purchased rebuild alternator that
won't put out more than .5 volts. I took it back to the
auto parts store where I bought it and it tested good.
I have continuity through all the wires in the diagram.
When I pull the alternator's charging wire and start the
truck I only get .5 volts. When it's on the testing
machine at the store it passes.
I pleaded my case to the store and they gave me another
alternator and once installed I still get the same
result.
If I had a short in the wiring (which I find continuity
and nearly no resistance in) I should still see the
alternator putting out around 14 volts without the
charging wire connected to the post.
Any ideas?
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frontierguy
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| Posted: Jan 24 2011 at 7:50pm | IP Logged
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Does the "BATTERY" light work when you turn the key on???
You may have a fuse or fusible link blown. How can it put
out if it isn't connected??
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'10 Altima SL
Traded 08 Frontier for 16 Frontier SV CC Long box, quite an upgrade. I do miss the 6 speed and Dynomax ex.
Nissan Technician 25 + years
2011 John Deere X720SE
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j.obfuscation
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| Posted: Jan 25 2011 at 8:32pm | IP Logged
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It should still put out voltage because the belt is turning the alternator.
There are only 3 fuses associated with the charging system and all check good. I have continuity through all the wires.
When the positive lead is off of the alternator and you put a meter on it and a ground you should see about 14 volts. Since I only see .5 volts it looks like an alternator problem.
But, having gone through two new alternators I do not think this is likely.
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frontierguy
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| Posted: Jan 25 2011 at 9:15pm | IP Logged
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With the positive lead off - it's not going to charge!!! IS
THE BATTERY LIGHT ON WHEN YOU TURN THE IGNITION SWITCH
ON???????
__________________
'10 Altima SL
Traded 08 Frontier for 16 Frontier SV CC Long box, quite an upgrade. I do miss the 6 speed and Dynomax ex.
Nissan Technician 25 + years
2011 John Deere X720SE
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j.obfuscation
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| Posted: Jan 28 2011 at 10:19am | IP Logged
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OK, maybe I'm not being specific enough:
With the positive (charging) lead off of the Alternator
and the engine running, if you put a meter across the
positive (charging) lead of the Alternator and the
ground, you would see at least 14V DC regardless of a
short in the vehicles wiring. This is because the
Alternator is not connected to the vehicle with the lead
removed. When I do this, I get around .5V - 1V.
There is not charge light because, as is an all too
familiar problem with 98 Nissan Frontiers, the single
crappy chip that controls the instrument cluster failed.
The charge light is simply a voltmeter anyway and I have
a meter. If the cluster was working the light would be on
because it's not reading what it should be from the
alternator.
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frontierguy
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| Posted: Jan 28 2011 at 6:47pm | IP Logged
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The first check for a Nissan charging system concern is to
verify the BATTERY lite operates with the key on engine
off, if it does not, the alt won't charge due to the bulb
being blown or a problem in the circuit. I have never
checked alt output with the pos lead off, so I quess I'm
missing the boat here.(and I have checked a couple in over
36 years).
__________________
'10 Altima SL
Traded 08 Frontier for 16 Frontier SV CC Long box, quite an upgrade. I do miss the 6 speed and Dynomax ex.
Nissan Technician 25 + years
2011 John Deere X720SE
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j.obfuscation
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| Posted: Jan 30 2011 at 7:08pm | IP Logged
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So you are saying that if the charge indicator circuit is
open then the alternator won't charge? That seems a
little strange.
The alternator generates voltage from the physical
contact of the brushes and stators. I don't see how an
indicator light would negate the physical voltage
generation.
To isolate the alternator and eliminate all other
electrical circuits as a point of failure, isn't removing
all the wires (and thus their circuits) while running the
vehicle and checking the alternator's output a valid
check?
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frontierguy
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| Posted: Jan 31 2011 at 6:35pm | IP Logged
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I'm not a back yard mechanic with hocus pocus testing
procedures, I used to perform the basic test which the
first step is to verify that the battery lite operates with
the key "ON", this is part of the field wire circuit which
is critical to the operation of an alternator. Now we have
a GR-8 tester that performs all the test for us. I don't
have the ability to test an alternator out of the vehicle.
I am only trying to help you by stating that the first
basic test is to verify the battery lite is operating. If
all your alternators are testing OK, I would start with the
lite check to verify its operation. Other than that, I
guess I'm not much help to you.
__________________
'10 Altima SL
Traded 08 Frontier for 16 Frontier SV CC Long box, quite an upgrade. I do miss the 6 speed and Dynomax ex.
Nissan Technician 25 + years
2011 John Deere X720SE
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NalleyJ83
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| Posted: Jan 15 2012 at 7:15pm | IP Logged
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I seem to be having the same problem as this other guy. I'm willing to listen to what you have to say cause i'm not too much of a mechanic. So far i've went through 2 brand new altenators and 3 brand new batteries. The battery light does come on when I turn the key. Its been an off and on thing for quite a few months now. Its really frustrating i'd really appreciate the help thanks.
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j.obfuscation
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| Posted: Jan 15 2012 at 11:21pm | IP Logged
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So it turns out "master mechanic" here was right. Nissan
decided they wanted to make sure the voltage regulator
indication light was working before they'd let the
alternator charge anything. (First WWII and now this,
domo arigato nippon).
The whole story is that I had a bad instrument cluster
which is a common problem with 98 Nissan Frontiers. In
fact they don't make replacement clusters anymore. Nissan
made a poor cluster, changed it the next year, and
laughed at you if you bought their defective product.
Luckily there are folks who can repair them. This guy
fixed mine: http://autoxpresstech.com/
Anyway, my cluster was dead after having erratic
readings, so I was essentially testing all these good
alternators and thinking they were bad because, in a 98
Nissan Frontier, the alternator won't do a thing unless
it's voltage regulator has a connection to it's
ridiculous little light in your cluster.
By the way, it's not "hocus pocus testing"; it's called
"isolation" which is step one of the troubleshooting
process. I guess if you did your whole career rigidly
following steps in a shop manual thinking outside of the
box isn't your specialty. I do appreciate your advice and
if I would have considered it more I would have saved
myself a lot of time.
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Nissan Frontier Forums : Problems / Technical
Topic: Good Alternator not charging ’98
