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Alternator not charging, no light


moalaska

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It was about 10 degrees today.  Started truck and at first battery light lit, revved engine, then light was just sort of flickering for a bit until truck warmed up.  I wasn't worried because it was super cold and this stuff happens in Alaska.  Later on in day I noticed voltage guage reading 12 volts.  Checked with multimeter and battery not charging.  Would not restart.  Weird thing is the battery light wasn't on. Is it possible that the battery light just burned out, and caused the field not to energize?

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It's ....... possible. Also possible the brushes are frozen, plastic plug in the back is loose, output cable loose, battery cables loose or corroded.

 

Does the starter click or engage at all???

Do the headlight work slightly?

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Clean battery cables and posts.  Also be sure to take the fusible link plug off the side of the positive battery cable and give it a good cleaning also.  This gets missed when cleaning the terminals.

 

Start with the basics first.

Edited by Charlie69
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17 minutes ago, datzenmike said:

It's ....... possible. Also possible the brushes are frozen, plastic plug in the back is loose, output cable loose, battery cables loose or corroded.

 

Does the starter click or engage at all???

Do the headlight work slightly?

It's not a battery issue it's a charging issue.  Will jump start fine, but voltage drops and drains when jumper cables unplugged.i moved all cables around, and checked continuity on the fusible links.   I had enough juice in battery to restart it, when I turned on headlights it died immediately, and now it won't start at all.  I'm wondering if a fusible link was on last leg and the headlight circuit killed it.

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13 minutes ago, moalaska said:

It's not a battery issue it's a charging issue.  Will jump start fine, but voltage drops and drains when jumper cables unplugged.i moved all cables around, and checked continuity on the fusible links.   I had enough juice in battery to restart it, when I turned on headlights it died immediately, and now it won't start at all.  I'm wondering if a fusible link was on last leg and the headlight circuit killed it.

Now fuel pump not turning on.  Electro injection

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16 minutes ago, datzenmike said:

Headlights have their own fusible link. If blown everything else with still work.

 

 

Pulled random fuses and it restarted.  I think the ecu had some solid state timed fuse if not enough amperage, when I turn on headlights it died.  Still not charging and no battery light

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I never seen a burn out bulb

my 521 when the ign light wasn’t on it the alternator would pop my fuse.then popes my electronic volt reg.

 

ita easier to have alternator checked than pull a dash.

 

IF you have the schematic one could ohm out the wires that go thru the light bulb and find a EZer access to the connectors than pull the dash

Edited by banzai510(hainz)
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19 minutes ago, Charlie69 said:

If the fusible link connection on the battery terminal does not have a good connection it will not charge.  I have had this problem on 2 different trucks.

Fusible links had 12 volts on other end and continuity, that was first thing I checked.

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5 hours ago, thisismatt said:

Does the light come on anymore in the key-on-engine-off position?

Light doesn't turn on with key in on position or running.  Where does battery light get power from, and where at on alternator does other end of battery light circuit attach?

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I found this good info on Nissan alternators

 

http://datsun1200.com/modules/mediawiki/index.php?title=Alternator_Wiring#Late-model_Alternator

 

http://datsun1200.com/modules/mediawiki/index.php?title=Basic_Alternator_Wiring

 

So I believe either my charge light must be burned out, or the charge light isn't receiving power for some reason.  This referenced website mentions that a relay turns the dash lamp on and off.  

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The charge light has 12v on one side and charge from the alternator on the other. When you turn the ignition on the 12v from the battery is only on one side so it travels through the bulb to ground through the diodes and the bulb lights. When started and the alternator begins charging, there is equal voltage on both sides and the lamp goes out. 

 

No charge light could be a blown dash light or plastic plug in back of alternator off, loose or not making contact or the alternator is damaged.

 

  

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2 hours ago, datzenmike said:

The charge light has 12v on one side and charge from the alternator on the other. When you turn the ignition on the 12v from the battery is only on one side so it travels through the bulb to ground through the diodes and the bulb lights. When started and the alternator begins charging, there is equal voltage on both sides and the lamp goes out. 

 

No charge light could be a blown dash light or plastic plug in back of alternator off, loose or not making contact or the alternator is damaged.

 

  

I did some further testing.  Pulled the plug on the alternator.  Had power from battery, and with ignition on the other pin had power through the battery light circuit.  The ground wire has continuity and other positive lead has power as well.  So I guess it's possible that the battery light wire is not able to complete ground through the diode.  I might as well upgrade to the quest alternator since I already have the correct plug for it wired in.  

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On 12/6/2019 at 12:32 PM, datzenmike said:

The charge light has 12v on one side and charge from the alternator on the other. When you turn the ignition on the 12v from the battery is only on one side so it travels through the bulb to ground through the diodes and the bulb lights. When started and the alternator begins charging, there is equal voltage on both sides and the lamp goes out. 

 

No charge light could be a blown dash light or plastic plug in back of alternator off, loose or not making contact or the alternator is damaged.

 

Alternator tested dead at Napa.  Got 145 amp 2004 Nissan quest alternator, it was same price of stock alternator.  Installation was pretty straight forward, swapped pulley, ground down a couple spots on mounting bracket and bottom of alternator for better fitment.  The alternator mounting tabs lined up perfectly out of the box.  Had to get a longer back mounting bolt.  Extended the adjustment bracket with a couple of L brackets sandwiched together attached to the top alternator hole.  Ran 4 guage power from battery to alternator, attached a 4 guage ground from top alternator hole to the ground point on the battery box.  Used NAPA belt 7385.  Puts out 14.7 volts with everything turned on and heater full speed.  

Edited by moalaska
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Sometimes it's difficult to attach to the battery positive so I ran the thick alternator output cable to the starter lug.

 

 (the 100amp output cable was actually larger than my stock Datsun cable from the battery!!!)

Et2H8bx.jpg

 

Later I replaced the battery and all I could get were side mount terminals so I replaced the Datsun ones with ones from a GM...

 

Original cable in hand and thicker cable over to the right...

olzimFi.jpg

 

Ran the negative battery cable to the starter bolt.

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