Not-Charging Frustration

[idi_econoline]

Still no charging. Stays at 12.6 or so, idle and above idle.

Considering testing output at alternator output terminal while running. In a van, that would mean a long clip lead or two, with the inner doghouse off. That would indicate if output cable really is bad.

 

[idi_econoline]

Hmm, turns out that O'Reilly has the alternator connector, only a couple miles from me. If the output terminal test fails, this has to be the issue. Sound reasonable?

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[stick_witch]

However, since it's only running on one v-belt, it won't be anywhere near 130, so I think a 125 fuse will be fine.

I would definitely not recommend this. The 130 amp rating is just the normal operating amp output; around 2500 rpms, but these alternators have a max output of much more: about 170 amps. You’d be surprised what the single v belt will pull, and if you get going at anywhere over 2500 rpms theres a good chance you will blow that fuse eventually.
Don’t skimp out, just get a 175 amp, or at the very least a 150 amp.


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[stick_witch]

Still no charging. Stays at 12.6 or so, idle and above idle.

Considering testing output at alternator output terminal while running. In a van, that would mean a long clip lead or two, with the inner doghouse off. That would indicate if output cable really is bad.

Yep, test that, could also be not getting a good ground through the case to the mount. Make sure your connection from the solenoid to the battery is good too.

Hmm, turns out that O'Reilly has the alternator connector, only a couple miles from me. If the output terminal test fails, this has to be the issue. Sound reasonable?

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Not a whole lot it could be since it’s internally regulated, its either a bad alt/regulator, bad or incorrect pigtail and stator connections, bad b+ output, bad ground, or a bad or insufficient connection to the battery/solenoid.


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[idi_econoline]

Yep, test that, could also be not getting a good ground through the case to the mount. Make sure your connection from the solenoid to the battery is good too.


Not a whole lot it could be since it’s internally regulated, its either a bad alt/regulator, bad or incorrect pigtail and stator connections, bad b+ output, bad ground, or a bad or insufficient connection to the battery/solenoid.

Both yellow/black sensor wire and alt-solenoid wire are good. Bad ground thru mounting bracket not impossible, as both alternators (old and new) have the current issue in situ. Suspecting the prongs in the female pigtail connector. If the alt runs with 0v sensed, though, would it not charge super-hot? Or would it respond with no charge? (Not a great electronics wiz. Can read a schematic, but, got a "C" in 8th grade electronics!)

 

[idi_econoline]

OK: alternator ground good.

Voltage at alternator output terminal, even revving: 12.51v.

Off to get new alternator connector.

Remember this, from when I started this thread? My intuitive nature often knows, early on!

What's left? Wiring to the alternator?

 

[idi_econoline]

BTW, I had to DIG AROUND in the connector to get readings on that yellow/white hole in the connector.

Feeling quite confident that the prongs in that part of the connector are broken, meaning no voltage to the regulator....

 

[idi_econoline]

Soldered on new connector.

STILL NO CHARGE.

Got no words.

 

[stick_witch]

Soldered on new connector.

STILL NO CHARGE.

Got no words.

Something is not right with your wiring or alternator/regulator. Get rid of ALL the stock wiring and rewire with just the new pig tail and some that you picked up and some 14 gauge. Heres a wiring diagram of how it should be.

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DON’T wire based on color! There is an “a s i” stamped into the 3 prong plug on the back of the alternator, wire based on this diagram.
But, instead of taking the “a” wire straight to the solenoid, cut the stock wire out and just use the length given to you in the new pigtail, crimp a loop connection onto end and connect it back to the alternator at the b+ output post along with your 4 awg output wire. Some don’t like to do this, but it won’t hurt anything, and in your case it will just help deduce the problem and simplify things. The “a” wire is just your 12v power for the regulator.

Then take your “s” wire with your stator plug end and plug it into the male stator prong on the alternator. Make sure the plug on your wire and the prong in the alternator is in good shape and is making a good connection, otherwise just go buy a new stator plug and solder it on, and clean up the plug on the alternator with sand paper. The female stator plugs are like $5.

Then take your “i” and make sure its connected to the cab battery warning lamp wire where it was originally. This could also be your problem. If your battery warning lamp in the cab is out and the circuit is broken the regulator may not be kicking the alt on. The blue bubble on the wiring diagram i posted explains this and how to resolve it, I have never experienced this myself though.

Then of course, check your connection from the b+ post, to your megafuse, to your solenoid, and then to your battery. If you’re not getting power to the “a” wire, then the alt reg won’t get power, and then your stator won’t get power, and it cant produce power, and if you don’t have a sufficient connection from the alt to the battery you won’t get a charge from the alternator.

And of course, make sure you’re alt has good belt contact, you’re running the correct pulley configuration and that its spinning in the right direction. You could have a counter clockwise alt when you motor spins it clockwise. Not sure if the 3gs came in a counter clockwise variation.

Thats all I got. If none of that works then I’d try a new alternator/regulator. The circuit is pretty simple other than that “i” wire that goes to the light in the cab, so maybe check your wiring there and check that the light is functioning. Power Probes are great for that kind of stuff. Best tool a $100 can buy imo.

When you have everything connected like I said, post pictures that clearly show what is connected where at the alternator, and then pictures of your solenoid and battery connections as well. Maybe we can point out something that you missed.

Good luck!


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[idi_econoline]

Ooooo, yikes, Stick Witch!

That's a lot to digest, but, thank you. Still puzzles me, as all this started after working on brake hydraulics for 3 weeks. All was well when I drove it into driveway for that work.

"New" reman alternator I got two weeks ago giving same results as "old" alternator, so yeah, wiring. "New" alternator tested at store... is 15 volts too hot?

Will take my time with this, as the big, fat battery positive terminal on the passenger side is cracked and not making tight contact, and needs replacement Guessing THAT wouldn't cause my issue, would it?

Thanks again for sticking with me on this, Stick Witch. Good time to also install mega fuses on both alternator and glowplug cables.

 

[idi_econoline]

The GOOD news is that the alternator plug IS wired per your diagram, Stick Witch.

Took your advice, removing the alternator to solenoid wiring.

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But, wait, WTH is that green wire at the end.... OHHHHH! The green warning light/exciter wire!!!!!

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AND there's a corresponding plug, with a green wire, hanging next to the new brake booster!!!

Soooo, am I correct that THIS would be my issue, in that the alt was not getting excited????

It makes perfect sense, as I must have touched these plugs when I removed and installed the brake boosters.....

Thinking I will re-install the old wiring tomorrow, which looks fine otherwise, and hopefully I will have a good charge.

My question is finally answered: How could working on the brakes damage the charging circuit????

Now we know, and I am so relieved. I do know an excellent auto electric specialist, but I would have spent big bucks, to have them laugh at me!

 

[stick_witch]

Hahaha yeah wiring is a tricky subject to diagnose over forum, just figured I’d lay it all out so it’s there for you.
Yeah no worries! Happy to help!


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[stick_witch]

Oh good! That seems promising! My understanding is that if that green (aka “i”) wire is not connected or has a bad connection or the battery light is out on the dash, then yes, the alternator won’t get excited, and it won’t charge. But then again, thats just a guess. I’d imagine if it worked before you worked on the brake booster and you had unplugged that plug during the repair, that you can safely deduce it to that being your problem.

I hope it works out for you tomorrow!


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[idi_econoline]

TYVM, Stick Witch. Today (after work) was a roller coaster.

WTH, the connector next to the booster is also a 4 pin female!

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But, the one next to it is the one, clean and ready. The two don't latch completely, so I pulled them apart when I removed the battery. (at right in pic)

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But, after too many cycles of overtightening in recent days, the positive terminal on the starter solenoid broke. Calling it a day!

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Patience, Grasshopper.

 

[idi_econoline]

My understanding is that if that green (aka “i”) wire is not connected or has a bad connection or the battery light is out on the dash, then yes, the alternator won’t get excited, and it won’t charge.

Forgot to mention, Stick Witch, that, while running and not charging, the alternator warning light did NOT come on.