Charging system problem, help!

Exactly right. Easiest checks would be wiring continuity. Or if it's running at idle and no load what is the voltage you measure?

 

I would have replaced the alternator by your first post. (11ishV while the vehicle is running)

 

Alternator is less than 2000 miles old

 

But it should be putting out 13V+

 

Correct. And it will on and off. That’s why the battery light has been coming and going. I’m going to check the belt tension again cause I have a bit of a squeal when I start it up.

I’ve never had it die either since having the light come on which makes me think the alternator is charging just not enough.

 

Probably going to just take it to my family mechanic cause I dont have much time right now to be messing with it.

 

attached is the diagnostics from the FSM. On the rear of the alternator is a test port. When you insert a screwdriver and ground the field circuit it "full fields" the alternator and forces it to charge at its maximum capacity. This is a test of the overal system. If there are questionable grounds, the alternator will not work at all. The charge indicator light in the combination meter has a diode in the circuit. This diode allows for voltage to flow only one way. If the voltage in the battery exceeds the voltage put out by the alternator the light lights. Is this diode the issue, I doubt it but it is a possibility, either they work or they dont.

Remanufactured alternators are a hit or miss thing. They dont spend too much time on "remanufacturing" these things. Disassemble them, clean them and maybe put in new parts. Most of the time the commuator, thats where the brushes ride, is so worn that new brushes make poor contact. If they turn the commutator to clean it up you are hoping that they turn it on the center of the alternator shaft. If they turn it even .001" off, at RPM, it is enough for that to act like a camshaft and throw the brushes away from the commutator and you will get a fluttering light in the upper RPM range. Heat effects the diodes in the alternator too. If the battery is defective, like mentioned above, the alternator is trying to charge a bad battery and the alternator never gets a chance to "cool off", it is working all the time and that shortens the life of the electronics inside the alternator.

You might need to take her to an auto eletronic shop, not your local mechanic or the dealer. Most of the time these "simple" jobs are dispatched to the new tech and they are expected to be parts replacers as they are not "taught" diagnostics, they learn from trial and error. I am not bagging on your tech or your shop at all, I just know that this is how repair shops opperate ... most of the techs all they want are the gravy jobs and anything that requires diagnostic time is a waste of theirs.

 

Bummer, at least you didn't have to pay for the battery.

Are you getting the same voltage (11v) when it's running even with the new battery?

While this next thing shouldn't be "the" problem, you may also want to consider the "big 3" upgrade. It won't really "do" much if you aren't running high current items like lights or a winch or anything, but replacing the old stock alternator wires with new ones may remove a variable (bad ground, loose connection, etc...).

Any chance your alternator is still under warranty too??

 

Alternator is still under warranty, not sure I would want to get another reman though. I'd rather try to get a "new" one. I have a hella 750 lights, hella 500 fog lights, and some LED pod reverse lights.

 

Yeah, you may or may not notice a difference in the lighting. The OEM wiring is more than enough for the stock alternator output. Bigger wires don't really help, but they can't hurt either. The big 3 is most noticeable when you get a high output alternator and need the bigger wires for the higher current.

In your case, you probably wouldn't need to go as big on the wire gauge, but all new wire/connections couldn't hurt.

But what do I know, I was wrong about your battery, lol...

 

I went home at lunch today and tried to fix it as usual.

1st: disconnected battery terminals, cleaned, and reassembled. Battery light still on.

2nd: sprayed the B+ terminal with CRC electronics cleaner. Tightened the nut another HALF TURN. I was able to do this last week too. Battery light turned off.

So this nut either keeps loosening up or there is some bad internal connected in the alternator. Any ideas on this?

Does anyone have the torque spec for the alternator terminal?

 

We're getting somewhere. Might be bad connections or grounds in general(which it kind of sounded like in beginning as well). I'd double check all connections in charging circuit. I've had very good luck with boiling or very hot water cleaning the battery terminals and cable connectors. Any little bits of corrosion in this circuit can keep full voltage from making it to the battery. If you have the original alternator still, I'd put brushes in that and reinstall as the OEM Denso alternators are of very good quality.
Glamisman above posted very good info. I'd be reluctant to use a shop as well. Maybe taking the alternator into a electric/electronic repair and parts shop is an option. Those guys are generally well versed with this stuff

 

Sadly I returned my OEM alternator for the core refund.

 

Gotcha. Yeah that's normal. Most just don't know the remans are typically not very good quality. Doesn't matter now. You're still fixing your stuff

 

The alternator B+ terminal has a nut to hold the plastic insulator on, then the cable terminal, then another nut on top of that. I don't think the torques are very high. If you tighten the inner nut too much it can crack the plastic insulator. There might be some washers in there too. I don't think the torque specs are very high. The inner nut maybe a little more than the outer nut.

 

OP, you mentioned belt tension earlier. Did you check it? Should be 100 lbs., IIRC.

 

Hmmmmm mine only has one nut that holds the insulator and the cable on. This might be my issue.... What should I do from here, I might've cracked the insulator cause I can still tighten it more and more.

Light came on again today and I was able to tighten it another turn or so. I used a torque wrench and torqued it to 15 N-m (a little more than the spec cause it keeps coming loose). Light went off immediately.

Can anyone else confirm this "two nut" theory. All the parts diagrams seem to only have 1 nut.

 

Put an alternator in it. I'm going to bet they didn't replace the brush pack when the alternator was remanded, voltage that comes and goes like that is usually related to brush issues.

 

If that were the case then tightening the B+ nut would not fix the issue.

 

It might if the alternator was marginally functional. Have you removed the nut and inspected the threads on both the nut and clamp bolt?