M1078 100amp alternator charging issue

[DiverDarrell]

Well I have got a new 200amp alternator kit installed, and guess what? Yep no power. Which TM would I find the wiring diagram for this vehicle? Something is causing the alternator to not engage. I am wondering what TL6 the small wire from the 24v alt stud goes? Maybe this is my issue? I am at a loss and out of money LOL

Alternator
N1216 200 amp
Regulator
N3029


Actions Taken
Jumped 24v from the PDP stud to E on the regulator
Disconnected F from the regulator.

 

[Suprman]

The field is not flashing you need 24 volts at the regulator positive lead for the alternator
to make power. Go inside the cab to the power panel put a bolt into the 24v post left side of the panel and run a temporary wire to the regulator positive connection its the forward one and its red.

 

[DiverDarrell]

thats what i did, verified 24v on the regulator. im going to pull k11 and try the jump again

 

[Suprman]

Disconnect the wire that's originally there it may be shorted. Run a test wire from the 24 volt post to the regulator post. Make sure no other wires are on the regulator post at the time.

 

[DiverDarrell]

No luck

Disconnect the wire that's originally there it may be shorted. Run a test wire from the 24 volt post to the regulator post. Make sure no other wires are on the regulator post at the time.

 

[Suprman]

Are you sure? Nothing on either regulator lead. Make sure you have 12 and 24 volts from the batteries at the two alterna to main terminals before you run the truck. Once the truck is running out 24 volts to the regulator positive.

 

[DiverDarrell]

That's what I have done. I will double triple and quad check.

 

[Suprman]

Make sure the 12 and 24 volt are on correctly. Something is causing the field not to flash. And verify output voltage with a digital meter. I have seen plenty of bad dash gauges.

 

[DiverDarrell]

Ok so I am in the military, and should know better about assumption . When I took everything apart I had to label the main cables going to the alternator as the metal tags were missing. Easy day tagged 12 for the 12v stud and 24 for the 24 stud. Well. The last guy to hook them up in the army did it wrong, and I only checked for voltage and not what voltage. So I I'd a double check paying better attention and holly crap, flipped them and I have power. Charging batteries now and got to clean up the jumpers .

Seriously thank an you for the help on this, and now I wonder if I have a good 100amp alternator?. Haha. Some lessons need to be learned the hard way.

 

[Suprman]

The alts are beefy it should be ok. Is the alt making voltage now?

 

[DiverDarrell]

Will your my hero, making voltage like a champ. I'm an E7 and just today I was telling my E6 guys to trust but verify . I guess I need to listen to myself. Knowing what I know about the voltage regulators, it would have never excited the field with 24v on the 14 leg. One of the great design features of the niehoff, meant for guys like me.

 

[Suprman]

I remember way back in the day doing electronics upgrades in AAVs. There were guys from another unit rotated to our unit they knew what they were doing already and hooked the positive and negative both to 24 volts. Vaporized the negative connector pin on the unit they were using for testing. Came on since the base was bolted to the vehicle. Lucky they only ruined one unit. If the whole fleet had installed their gear all at once it would have been a really expensive day. I figured it out watching them hook it up I could see both power connections were on positive but no one else could see the obvious.

 

[Bobcat701]

I had a charging issue with mine. During numerous trouble shooting routes I found the anomaly. I had a broke grounding wire on my voltage regulator. It broke about an inch away from the VR, and was hidden by the intact shrink wrap. I would say it was diagnostic brilliance on my part however it was simple luck. The wire came apart when I was inspecting the VR. Even a Blind squirrel finds a nut every now and then. I am now back in the green when running.

Upon further inspection I realized that I was missing a part of my alternator mounting bracket. "I will start looking for one today." My hypotenuse is due to the missing bracket it causes the alternator to vibrate more. Thus breaking the wire. Upon my return home I will post a pick identifying the wire described. Just fixed it yesterday.

Regards,

Joe

 

[SS WFO]

just getting to know my alternator I had it working (green lights wig Wagin).Ten minuets later I got red and amber wig wag volt meter reading 24.3

 

[Ronmar]

just getting to know my alternator I had it working (green lights wig Wagin).Ten minuets later I got red and amber wig wag volt meter reading 24.3

Well thats about 4v low. What did 12v read? It having lights on the reg, indicates it has enable power applied. That is the forward screw terminal. Measure it, it needs to be at least 21v. It gets applied by K11 once the engine has proper oil pressure. Its probably OK.

That being said, alts either cannot make adequate power to supply the normal load(bad alt/reg), or it is receiving more load than it can power(overloaded). This dual volt throws a third wrench into the gearbox. It is designed to act as a battery balancer. If it cannot see a proper 12v out of the middle of the 24v series wired batteries, it will not operate properly. so when collecting data, measure 12mand 24 at the alt and 12 and 24 at the batts. Also check the batts individually. Static resting voltage(12.6-12. on each battery, and load test them…

 

[coachgeo]

side question.... if the excite voltage is less than 24v.... will it/will it not... excite the alternator?

 

[coachgeo]

Ok so I am in the military, and should know better about assumption . When I took everything apart I had to label the main cables going to the alternator as the metal tags were missing. Easy day tagged 12 for the 12v stud and 24 for the 24 stud. Well. The last guy to hook them up in the army did it wrong, and I only checked for voltage and not what voltage. So I I'd a double check paying better attention and holly crap, flipped them and I have power. Charging batteries now and got to clean up the jumpers .

Seriously thank an you for the help on this, and now I wonder if I have a good 100amp alternator?. Haha. Some lessons need to be learned the hard way.

wait... so how did you still have 24v showing on the dash yet have the leads swapped?

 

[GeneralDisorder]

wait... so how did you still have 24v showing on the dash yet have the leads swapped?

He had the leads to the alternator swapped. Not the battery terminals. The alternator sees one side is high and one side is low and shuts down - thus the flashing amber and flashing red LED's. Once the alt drops offline out of the system the gauges read battery voltage.

 

[MatthewWBailey]

This has been another episode of the electrical Olympics, sponsored by FMTV. Thanks for watching.

 

[coachgeo]

side question.... if the excite voltage is less than 24v.... will it/will it not... excite the alternator?

Bump in case it got lost in the Easter Egg Hunts