Back to the ol' alternator issue.....

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UncleTone

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Yup, and another thread. 2014 5.7L. I seem to be going in circles here. So I had the "alternator not charging problem". Battery light is on first and goes onto battery save mode and then says battery voltage low. I replaced the alternator, nothing, recharged the 3 month old battery, nothing, replaced the PCM, nothing. So I'm back to the drawing board. Battery right now is at 12.6 with the engine off and drops down to 12.3 when the engine is on. No charging nothing. Ive tested the plug going into the alternator and it seems to be fine. Its just not getting the signal to start charging. Ohm reading on all the wires between the battery and alternator all good. TIPM fuses are good and working. TIPM is getting the same reading as the battery. Im wondering if it could be the battery control/temp sensor attached to the negative terminal, but if I jump the plug with a wire nothing happens. Is there anything else I'm missing here?? Im stumped and don't know where to go. Are there any other inline fuses that I'm missing?? I know the voltage regulator is powered in the PCM. Any help here????
 

Brandon-w

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Have you tried adding power to the field winding on the alternator? The one the pcm is supposto energize? That should make it start to charge do and if it doesnt money is on ur alternator.
 
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UncleTone

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Have you tried adding power to the field winding on the alternator? The one the pcm is supposto energize? That should make it start to charge do and if it doesnt money is on ur alternator.
So I actually tried that field test. I placed a wire from the + to each one of the 2 connections on the alternator. One connection nothing happened and on the other one I could hear a faint noise coming from the alternator, with a little spark from touching wire to prong. Although I did not notice any difference or change in the reading from the battery. It sat at 12.34.
 

Brandon-w

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So I actually tried that field test. I placed a wire from the + to each one of the 2 connections on the alternator. One connection nothing happened and on the other one I could hear a faint noise coming from the alternator, with a little spark from touching wire to prong. Although I did not notice any difference or change in the reading from the battery. It sat at 12.34.
Not to sound dumb/rude but the truck was running right? If this is the case I'd definately take the alternator off and find a parts place that can test it for you or swap it out if there is warranty. To me sounds like a dud if everything else checks out correctly.
 
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UncleTone

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Not to sound dumb/rude but the truck was running right? If this is the case I'd definately take the alternator off and find a parts place that can test it for you or swap it out if there is warranty. To me sounds like a dud if everything else checks out correctly.
Yes, the truck was running and totally died out. I did put a new alternator in the truck, doesn't mean that it works correctly. I was basically getting the same problem with the original alternator but I did not do any checks on it, just simply replaced it. The new alternator is under warranty so I will take it to the store and check it and possibly get a new one. Thanks
 

Brandon-w

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That's definately where I'd start. Sometimes they crap right ouda the box. But considering power was added with no difference I'm putting my money on alt. Leme know how it goes. [emoji106]
 
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UncleTone

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That's definately where I'd start. Sometimes they crap right ouda the box. But considering power was added with no difference I'm putting my money on alt. Leme know how it goes. [emoji106]
Alright, so I went and had the alternator tested and it actually failed. I got another one, and it passed at the store. Installed it and right away it made whining noise when the truck started up and it slowly drained the battery. The alternators are not mopar, they are form auto zone, duralast. Could that possibly be the problem??
 

Brandon-w

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Alright, so I went and had the alternator tested and it actually failed. I got another one, and it passed at the store. Installed it and right away it made whining noise when the truck started up and it slowly drained the battery. The alternators are not mopar, they are form auto zone, duralast. Could that possibly be the problem??
Hmm that's very odd. Doesn't make any sense why it would whine and then voltage would drop. Kinda has me scratching my head.
 
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UncleTone

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Hmm that's very odd. Doesn't make any sense why it would whine and then voltage would drop. Kinda has me scratching my head.
Same here. Pretty sure the TIPM is good. Wires are all good. I don’t see a fusible link anywhere in the harness. New alternator is rated for 180amps. Am I missing any other sensors or anything like that??
 

Brandon-w

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Shouldn't be. Just the main wire that goes to the battery and the connector with the two wires in it. That's why I'm kinda dumbfounded, unless you got another crap one but two out of the box problems like that I'd say is damn rare. I'd try applying power to the exciter wire again and see what happens. This is too odd.
 
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UncleTone

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Shouldn't be. Just the main wire that goes to the battery and the connector with the two wires in it. That's why I'm kinda dumbfounded, unless you got another crap one but two out of the box problems like that I'd say is damn rare. I'd try applying power to the exciter wire again and see what happens. This is too odd.
First link is the alternator plugged in, second video is field testing.

 

Brandon-w

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That's quite a whine. That seems really weird.
 

turkeybird56

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Brandon- Improper tension on the serpentine belt, LIKE too tight, and pulling down on the alternator bearing??????

Cause he said it tested good from in the store...............

ADDED: Now a loose ground somewhere could cause the battery to not take a charge and Overwork the Alternator also..... Not sure about ne fusible links on a 2014.

CHECK all the ground points and also check the Negative cable-shorting somewhere, who knows...a Guessonosis on line is tuff
 

Brandon-w

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Possible but that couldn't cut off charging it would only cause a growl wouldnt it? Seeing as it's a set tensioner id expect looser conditions vs tighter in my opinion anyways.
 
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UncleTone

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Turkey, from my experience the belt seems pretty good, tightness wise. Im not saying that you are wrong at all. Also, food for thought, in the first video with the alternator plugged in, if I unplug while running, obviously the sound goes away but when I plug it back in there is no sound. Also could the difference between the 180amp and 220amp alternator be causing this?? The mopar alternator is 220.
 
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turkeybird56

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Man, I dunno. Really hard to guess over the internet. U already did all that I would think needed to be done. My thoughts on belt were just throwing out ideas. BUT, it is documented that a Bad battery/badly grounded Battery would cause the alternator to overwork and burn up. Just my $.27 on this. Cause really, U should be good to go. I do not know about any fusible links, I am just not smart enuf to know that. The last Alternator I played with was my passed wife alternator in her 2010 F150 which had the Triton motor, and that turned out to be a bad tensioner, which I replaced. I also replaced the battery just because, Momma's truck, U know.

SO Definitely check out all the grounds and the negative cable.

ADDED: If the belt is too tight, which I doubt, as long as turning alternator, it would charge but too much tension on that alternator make it moan and wear out bearing. U may have to check your area and find a reputable electrics shop to take it to. Might be cheaper than just throwing parts, just saying...


OTHER: As far as 180 amp vs 220 amp, the VR is in the alternator. Now on an old Chevy that not be an issue. But with these new trucks, with all the electronics, I am not sure. U gonna have to talk to a starter/Alternator/Electric shop on this. Maybe Brandon could chime in as I am no mechanic, just have an opinion (skerry)..........
 

chri5k

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With the engine running, carefully take your hand and feel all the wires from the battery and alternator that carry heavy current. Both positive and negative. Feel for any hot spots, bulges, etc. Also look at the red cables carefully to see if any of them are discolored in spots or sections. I have had 2 cases in my 40+ years working cars where a cable was fatigued by engine vibration. It looked good from the outside but the copper conductor inside was broken. When it was a ground cable it was cool near the battery and almost burned my hand when I got to the area where it was broken. The other case with the red cable, it was bright red up until the point it had a break and was a dark red around that point.

PS. they can test good with a meter when the engine is off but once the engine is running you get intermittent opens, high resistance and normal capacity randomly. Also have the battery tested. It may be only 3 months old but if it sat at or near 0 volts for even a short period of time, sulfation can short one or more cells.

PPS. You can also try bypassing all the ground cables with the black lead from a jumper cable by hooking one end to the battery negative post and the other end to the engine block or alternator bracket. If this works one of your ground cables is faulty.
 
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SYKRAMMAN

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Get yourself a power probe, that'll let you know exactly what's going on.
 
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