M1078 100amp alternator charging issue

[DiverDarrell]

Looking for help to diagnose why my alternator is not charging. The voltage regulator 14v light is solid red. Steps taken so far

1. Charged batteries
2. Replaced the N3207 regulator with a new one
3. Ensured all cables are tight that i could find
4. checked the K11 relay, and switched with a couple known to work

Is there anywhere where one could find a simple diagram on how the charging system is wired?

Should i try and jumper from the 24v+ to the E on the voltage regulator? in the niehoff wiring guide i see that there is a switch in there between the 2.

 

[NDT]

Did you visit the Niehoff website? There is a lot of good diagnosis info there.

 

[Overdrive]

I have zero experience with charging issues to date however, for what its worth, there was a bulletin about an issue with a fusible link failing that caused charging issues and was discussed within the forum. Somewhere right on the generator. bulletin told units to remove the link completely. I would have to do some digging to find the procedure but thought I would mention it anyway.

OD

 

[Suprman]

Disconnect both leads to the regulator. Tape up and abandon them. Take the outer connection on your fuel solenoid and run it around the engine to the positive 24 volt lead on the alt regulator.

 

[DiverDarrell]

Disconnect both leads to the regulator. Tape up and abandon them. Take the outer connection on your fuel solenoid and run it around the engine to the positive 24 volt lead on the alt regulator.

I jumped E on the regulator from the 24v+ on the fuse panel, all i got was a flash of amber on the 28v light, and then red flash on the 14, repeat and then solid red on the 14v. while the engine running and also when it was off. Supraman I will try your setup tomorrow and report back. I hope I don't have to buy a new alternator, seems all that's available is the 200amp kit. A big kick to the wallet on an enlisted mans budget lol

Does anyone one know what the AC lead on the regulator feeds?

 

[Suprman]

The AC lead is actually and alternating current output from the alternator. Can be used to drive a tach or other small accessory. No idea why it was ever connected to begin with. Some newer A1 trucks use the lead with a newer gen polarity protection smart box behind the cab.

 

[DiverDarrell]

Suprman, I did exactly as you suggested, I ate my dinner as fast as i could, so i could have a few more min to work on the truck, didn't want to wait until tomorrow. no joy... got a couple more things in the niehoff troubleshoot guide. Hopefully no blue sparks, as they are with the battery hot.

 

[Suprman]

If you have 24 volts from the fuel solenoid positive lead to the positive lead on the regulator and the alt still won't make voltage then the regulator may be bad. Measure make sure you have 24v at the regulator. Nothing should be connected to the AC lead. Measure the 12/24 at the alt output with the 24v regulator input disconnected then connected see if there is a difference. The alt regulators do go bad often. The 24v regulator leads usually go bad.

 

[DiverDarrell]

Thanks for all the help. Bought a new regulator, it was delivered today, and acts same as the old one. My alternator has the fuse studs installed, that the PS magazine says to remove. I will give that a whirl tomorrow removing them, as i recharge the batteries. I find it odd that even with the engine not running i get the same flashing lights. resistance test was sat through the alternator, my fingers are crossed that its the fuse studs. If not.... i'll be in the market for a new alternator. The battery load balancer wouldn't cause any of this would it? that box below the spare tire rack

 

[Suprman]

I'm still thinking you don't have a good 24 volts to the 24 volt lead on the regulator. Without this the alternator will not excite and just spin without making voltage.

 

[DiverDarrell]

I took 24v straight from the lug on the fuse panel. Metered it at 24.7v
just in case I'll jump straight from the battery post. I guess worst case I could always tow my generator behind the truck. Leave the gen running powering a 24v charger and a 12v charger to keep the batteries up. Just kidding.

 

[Suprman]

It's not a big issue you will work it out I wouldn't worry about it. 24 from the fuse panel to the regulator 24v lead should excite it. Engine running of course. Don't rely on the dash volt meter use a digital one to verify everything. And while you are at it check the alt ground strap for corrosion.

 

[DiverDarrell]

Well I tried it all, no luck. Went through the niehoff wiring diagram and I'm not getting continuity between pins on the plug and the 14v stud on the alternator that I should be. So I may be taking it all apart and learning how an alternator works first hand. And searching the Internet for a replacement n1511. I will also call niehoff and see if they can offer additional tech support on this issue. It has a 2008 alternator so it's not the original.

 

[Suprman]

If the regulator is swapped with a good one and the alternator will not excite and produce voltage with a good ground strap and 24 volts at the regulator positive post then the alt is probably bad. You could look at the pins on the connector from alt to regulator. Could be a bent pin or something. I can find you a replacement alt.

 

[DiverDarrell]

I think it may be a bad diode on the 14v leg. I'm getting 30ohms where I should be getting 0. I think I should be able to test the diodes if I take apart the pulley end. Suprman you will probably be getting some parts request from me real soon. Lol.

 

[Suprman]

The alternator is modular and pieces can be replaced. I have never taken one apart though. Here is a pic of some ends I have, but they are for a different alternator. Just to give you an idea.

 

[DiverDarrell]

Well this gives me confidence to tare into it. I don't think I could thank you enough for the help you have given me. FYI the new style air dryer I got from you only needed 2 additional parts to install. The universal mounting bracket and a larger hose to npt fitting for the 1/4" control air line. Just had to cut the bracket to fit around another bracket bolted to the frame and only 3 bolt hole lines up. But it's on there solid. Super easy switch to do, only took 15min to complete.

 

[Suprman]

Take it apart post pics. Somewhere I have an alternator from a truck that was crashed. The alt got a bit crushed but might have a diode module or other small internal parts that are still good. Post a few pics of the dryer install if you get time. I keep meaning to do mine just hard to find time for everything.

 

[DiverDarrell]

Well I took the alternator off, I wasn't able to get the drive end off, needs to be pressed and I don't have one yet. So further trouble shooting with the MultiMeter, i'm finding that the diode check between the Ground stud and the 28V is working, but the diode check both ways from the ground stud to the 14v is OL. I am guessing that the 14v Diode is shot. Dang it...... no 4th of july parades for this truck this year.

 

[DiverDarrell]

If anyone is wondering the Drive End Module is N7460. and instructions

http://www.ceniehoff.com/Documents/Ctrl_Hyperlink/II0094B_uid121020091146431.pdf