One of those dreaded alternator failure, replacement, still something wrong issue solved!

412 Views 13 Replies 3 Participants Last post by 2ndGenMaintainer, 4 d ago

2ndGenMaintainer

Discussion Starter · 8 d ago (Edited)

Hi Family!

Recently had the alternator brake and battery light issue. In this case, I had a bad voltage regulator harness found while removing alternator. Soldered and shrunk a new harness on improperly. Had same issue as before new alternator.

Key issue: charging system tester reading "charging high". Limp mode after driving a few minutes, but brake and battery light are off.

Solved in this particular case by correctly wiring new alternator voltage regulator harness.

For some reason I can't get into the nicoclub manual to verify wire color coordination. However, this link is to a video where this very kind gentlemen layed it out very easily.

The harness being melted before the alternator was replaced, was most likely causing the limp mode symptom. Still yet, after I replaced the alternator, I mis-wired the harness and it still had the same symptoms. The old alternator may have very well been fine in this case with a bad regulator most likely. Unfortunately, I won't know the answer to that question.

107k first replacement of alternator!!

100% honesty : failed to securely tighten battery post terminals. My negative bolt rusted/rotted and I thought I was tightening it while it was actually just spinning. I didn't catch it till now. My fault I think. Probably caused heat at the alternator voltage regulator harness connections. I did notice some corrosion on the battery terminals at time of service lol.

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jbarnett250

· #2 · 6 d ago

I think the melted alternator plug/harness thing is kinda common (seen a few videos of people repairing these) so I'm not sure your loose cable clamp was necessarily the root cause. I suspect I had a plug/harness problem in my 2nd gen too that intermittently caused a no-charging condition until I disabled the vvcs function that is controlled and sensed at that plug. But it's so tight to work in there I'm putting it off replacing the plug. I bought the replacement plug but am just dreading doing it. Did you drain the coolant and remove the top radiator hose and fans to do that plug splice job? And do it from the top or the side? Take any photos of your job? Would make a good DIY.

The FSM recommends to disable the vvsc as the first step in any no-charge troubleshooting by disconnecting the battery current sensor. This will tell you if your regulator is still good or not by disabling the external controls that could make it appear like your alternator isn't working. I couldn't get mine unplugged but that's how the FSM recommends to start troubleshooting to avoid misdiagnosing the alternator as bad. That looks like alot of tight and tricky work to DIY the alternator swap only to have the same problem after.....

You might try another browser if you can't get the nicoclub site to work. I can't get the manuals to work in Chrome but Edge(!?) works for me. Might just be some browser settings I've made in Chrome and never made in Edge because I never use it. Those manuals are key to figuring so much stuff out.

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2ndGenMaintainer

Discussion Starter · #3 · 6 d ago

jbarnett250 said:
I think the melted alternator plug/harness thing is kinda common (seen a few videos of people repairing these) so I'm not sure your loose cable clamp was necessarily the root cause. I suspect I had a plug/harness problem in my 2nd gen too that intermittently caused a no-charging condition until I disabled the vvcs function that is controlled and sensed at that plug. But it's so tight to work in there I'm putting it off replacing the plug. I bought the replacement plug but am just dreading doing it. Did you drain the coolant and remove the top radiator hose and fans to do that plug splice job? And do it from the top or the side? Take any photos of your job? Would make a good DIY.

The FSM recommends to disable the vvsc as the first step in any no-charge troubleshooting by disconnecting the battery current sensor. This will tell you if your regulator is still good or not by disabling the external controls that could make it appear like your alternator isn't working. I couldn't get mine unplugged but that's how the FSM recommends to start troubleshooting to avoid misdiagnosing the alternator as bad. That looks like alot of tight and tricky work to DIY the alternator swap only to have the same problem after.....

You might try another browser if you can't get the nicoclub site to work. I can't get the manuals to work in Chrome but Edge(!?) works for me. Might just be some browser settings I've made in Chrome and never made in Edge because I never use it. Those manuals are key to figuring so much stuff out.

Ah I see, ill try using a different browser thanks!

Thanks for the info about the vvc too!

I did the soldering and shrinking from the top, but this was before I attached the positive post to the alternator for slack purposes. Then I had to remove this regulator harness from the alternator after I realized I miswired it. So I took a wire hanger and made a long tool to depress the harness clip while I tugged up on the wires in order to pull the harness out from secured in the alternator. I then squeezed my hands in once again and just cut, soldered and shrunk tube on the wires again but making sure the colors were correct this time. Then I used a long extension to push the harness back into the alternator. It wasn't too bad, just a little tight getting down in there to twist the wires together before soldering.

While soldering, i unrolled a long lead of solder so that I could work it back and forth on the solder gun from up top. Held onto the soldergun/wand with my fingertips down and to the wire where I fed the solder onto the tip with it touching the bare parts of the joint and just worked the tip back and forth on the joint. Hope that makes sense lol.

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Skytechja

· #4 · 6 d ago

Hey good day...

Let me start by saying I Have a 2010 Nissan Murano Z51

QR25DE engine....

Im not sure if something similar happened to me but I've been driving quite fine and today out of the blue, the battery and brake lights come on.
I feel the van vibrate a bit when coming to stop and when I engage the air conditioner so the first thing to my mind was that the alternator is gone and I'm running from battery only.

Both lights were constantly on even if I tried revving the van (and it wouldn't rev much either).
after driving a bit I realize other lights on the dash started to come on but I had already shut off the radio and ac, unplugged chargers from the cig lighters etc just so that nothing would use any battery power.

I then noticed the VDC light on and shortly after the ABS light... So I'm thinking that the van is slowly shutting down non-essential services..... lol

finally light blinked on the dash and then van halted.. at a few intervals there was the smell of burnt rubber but thanks fully that wasn't my tranny or anything... ..

Later after inspecting the serpentine belt, I could tell that it got worn a bit ( So I may just get another right away).....

Reading a few posts they spoke about the alternator going bad and some spoke about the plug/wires being burnt

I noticed 2 connectors and 3 connectors to my alternator.... ...
1 - the main one with the 10 or 8-mm nut
2- a big 2-plug connector
3 - hidden in the back n very hard to reach with dismantling...another 2 wire connector, .. no idea what it is for

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I tugged on the 3rd one I just mentioned and the wires just came right out to connect the housing with the metal ends on them still, it sparked a lil too... ...

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This i will have to sort out and then check to see if i really will need to replace my alternator...

Oh, i bought the van with an alternator that had already been replaced.. and looking at the part number on my alternator, i realize the part number matches that of the Nissan rouge (12v \ 110A)

My original part number 231001AB1B - 12v\ 130A

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2ndGenMaintainer

Discussion Starter · #5 · 5 d ago

Good day!

Good find! Looks like you could try replacing that harness and see if it fixes all of your issues. Keep in mind that at least for the muranos, the alternator can be hit and miss lately on whether or not you get a good one and depending on the brand/cost. I say that because many of diyer here has reported bad out-of-the-box alternators or even ones that don't last very long at all. It was not fun changing the alternator and I dont want to have to do it again. BTW, I chose to drop the ac compressor to get the alternator changed out added a bit more time but alleviated the need to drain coolant and remove radiator/condensor. I got lucky with the Duralast gold so far, fingers crossed, knock on wood! Lol. Good luck and let us know how it works out!.

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Skytechja

· #6 · 5 d ago

2ndGenMaintainer said:
Good day!

Good find! Looks like you could try replacing that harness and see if it fixes all of your issues. Keep in mind that at least for the muranos, the alternator can be hit and miss lately on whether or not you get a good one and depending on the brand/cost. I say that because many of diyer here has reported bad out-of-the-box alternators or even ones that don't last very long at all. It was not fun changing the alternator and I dont want to have to do it again. BTW, I chose to drop the ac compressor to get the alternator changed out added a bit more time but alleviated the need to drain coolant and remove radiator/condensor. I got lucky with the Duralast gold so far, fingers crossed, knock on wood! Lol. Good luck and let us know how it works out!.

Yeah, I def will. A friend of mine is on his way to my location with my tool kit.

But what I wanna know... How different is the alternator for the VQ35de than the QR25DE...

one difference so far is that the VQ35de carries a 3-pin connector while the QR25de carries a 2-pin connector.

As for that connector that I'm not sure that is pictured in my post, I'm not sure what it is for but I'm kinda wondering if it has to do with the alternator sensing

For you to get to your alternator though, that sounds like ALOT OF WORK!!!!

Will update as soon as my kit is here

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2ndGenMaintainer

Discussion Starter · #7 · 5 d ago (Edited)

It was a whole hell of a lot of work.. I'll never buy a transverse v6 ever again.. sadly it seems all manufacturers except for Toyota are only concerned with ease of assembly, but not maintenance..

Here's what I found for 2 wire murano alternator wiring diagram. Not sure if its for your qr25de. It might be the correct diagram if there is a yellow/b-stripe and a brown wire there. If so, it looks like the brown wire is the sensing wire with a meter. I dont see any IPDM in this particular page.

I'

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jbarnett250

· #8 · 5 d ago

2ndGen, strange timing but I saw a Nissan Maxima dies while driving video today that sounds even more like your original failing alternator situation. Don't know if you've ever seen Eric O. on South Main Auto channel on youtube but he does a bunch of good diagnosis videos and this one happens to be on our exact charging system. In this video he gets a Maixma that goes into some kind of limp mode due to high charging voltage rather than the battery dying from low voltage. This one would flash the battery light sometimes. He ends up replacing the alternator and not the harness even though the Nissan dealership quoted $2000 to replace the harness. They must have been thinking it needed that plug/harness replaced too.

He cleaned up the battery connections in this one too because they looked crappy so maybe the loose battery connections had something to do with the original cause of the alternator failure after all.

Check out this video and tell me that doesn't sound like your car's behavior..... there's a part 2 where he completes the repair.

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2ndGenMaintainer

Discussion Starter · #9 · 5 d ago (Edited)

jbarnett250 said:
2ndGen, strange timing but I saw a Nissan Maxima dies while driving video today that sounds even more like your original failing alternator situation. Don't know if you've ever seen Eric O. on South Main Auto channel on youtube but he does a bunch of good diagnosis videos and this one happens to be on our exact charging system. In this video he gets a Maixma that goes into some kind of limp mode due to high charging voltage rather than the battery dying from low voltage. This one would flash the battery light sometimes. He ends up replacing the alternator and not the harness even though the Nissan dealership quoted $2000 to replace the harness. They must have been thinking it needed that plug/harness replaced too.

He cleaned up the battery connections in this one too because they looked crappy so maybe the loose battery connections had something to do with the original cause of the alternator failure after all.

Check out this video and tell me that doesn't sound like your car's behavior..... there's a part 2 where he completes the repair.

I love south main auto, my favorite!

I used to watch a lot of rainman Ray too but I think I just outgrew his content. Ray's a nice guy and a great mechanic but for some time now I've wished that his content would evolve a bit past the basics. Wish him well, but Eric O and Mrs. O are my all time favorite. Been a while since I've seen him do a two part on a diag. His methodology for troubleshooting is superb. A lot to learn from him for sure. He keeps it interesting.

Diagnose Dan is another superb diagnostician on YT. You may have seen him shouting out SMA a couple times.

It definitely sounds like the same exact issue I was having. Too bad I didn't find it before I bought a new alternator. Knowing my luck though, if I had, then I'd probably still need a new alternator lol!🤑🤑

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Skytechja

· #10 · 5 d ago (Edited)

Ok folks, quick update...

So I took the alternator out and pulled it and inspected it, everything look pretty normal, with no burning smell, no weird sounds or anything like that when u spin the pulley.
Cleaned it up a bit and put it back in the vehicle. Started the van with a jumper pack and as soon as the jumper pack was disconnected, the vehicle basically started struggling to keep up.

So my friends suggested trying a stronger battery, just in case mine was really on its way out.
So we put everything back together... Oh this is a battery that I was getting 12.5V from
Started the van... it was running though u could see it vibrating like it started to shut down a few systems...

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check the voltage of the battery...... I got 9.5v

so I will just go ahead and replace this alternator.

I didn't have my scan tool (not as advanced as the one in the video above) so I could scan the vehicle to know what's up.
But I know for a fact that it will show me that low battery voltage among a few other codes.

I also plan to run through as much wiring as I can n check ground connections.
I noticed I have a lil power steering fluid leak so I will check whatever wires/ground connectors or sensors are back there just in case oil may be messing with something else there...

Regarding the three-wire plug I mentioned, there seems to be some modification because the original alternator for the QR25DE in the Z51 Murano is rated at 130A (3 wires) and not 110A (2-wire plug)... Sorry, no pics of the voltage being tested... It was getting dark and the mosquitoes were out... lol...

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one thing I did notice though is that my AC compressor pulley is dancing... lol.. so I will have to get that addressed asap.. (that would explain the rough noise I hear few times when I come to a stop)

Though the condition of my belt looks good, I noticed that one side had more rubbing than the other..

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jbarnett250

· #11 · 5 d ago

Sky, sounds like all 3 of us need new alternators. Good job getting that out and back in so quickly. That looks like a tough job. Did you take it out the front or the side? Did you disconnect AC lines? Or drain coolant/move radiator? I'm trying to decide how to tackle this.

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Skytechja

· #12 · 5 d ago

jbarnett250 said:
Sky, sounds like all 3 of us need new alternators. Good job getting that out and back in so quickly. That looks like a tough job. Did you take it out the front or the side? Did you disconnect AC lines? Or drain coolant/move radiator? I'm trying to decide how to tackle this.

Not at all.

I took it out from the top. The only thing I moved for a lil space was my coolant bottle.

I have the QR25DE engine so I would have more space in the engine bay than the VQ35DE whose alternator sits lower.
My sis has the VQ35DE in her 2018 Pathfinder. I replace a strut on it the other day.. n wow the power from that engine... lol

N Yeah. def sounds like the alternator is the issue for all of us.. Sigh........

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Skytechja

· #13 · 5 d ago

Seems various owners experiencing similar issues with different causes. Almost everything pointing to the alternator.
I guess it is Weak point like the CVT transmission.

I started experiencing issues after changing the radiator neck on my murano.

Previous owners had water in the there so I drained the radiator, replaced filter neck n refilled with oil based coolant. But I realized every now n then I have had to top up with no visible leaking at all.
A friend suggested that there was water still in the engine pockets and it may be evaporating while vehicle in operation because it's mixed with the oil based coolant. The van does seem to run a lil hotter than before.

When my van shut down on me, wires to the alternator did feel soft...

I'm just here thinking about any n everything..

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2ndGenMaintainer

Discussion Starter · #14 · 4 d ago

Yeah thats kind of where it seems we all end up even with slightly different symptoms. It seems that it may just be a regulator problem and possibly not the entire alternator.

You may have air still in the system somewhere, but I assume you already ruled that out. Sometimes it can be the impeller inside the water pump failing. Or an intermittent power issue with the water pump. The temperature sensor is most likely intact. Worst case obviously possible head gasket, but I wouldn't hang my hat on that.

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One of those dreaded alternator failure, replacement, still something wrong issue solved!

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