200 amp generator / regulator that works periodically...

I recently pulled a lot of the front off my M1097A2 to replace water pump and install mechanical fan upgrade. While I was in there I checked the generator and it turned super-smooth by hand, so it seems to be mechanically OK.

With that said, my battery gauge lives in the mid-to-upper yellow during my short drives (I charge batteries while parked) until every so often I start it and it drives in the high green. Even had it stay green over three consecutive trips until it decided to go back to yellow while at a stoplight. Strange.

Anyone had this issue or heard of this issue? I am still learning EVERYTHING about how to diagnose issues and unfortunately I am semi-retarded when it comes to electronic schematics and equipment. My son-in-law is a Journeyman electrician, so I am trying to coordinate with him to help me - he just works 70+ hrs / week.

I have another regulator (used) that is supposedly good, but I am not burning up any other components after my break/turn light module fiasco. I plan to test everything first - but thought I would ask the board for any experience with this particular intermittent issue.

Thank you in advance!

My regulator worked intermittently. Sometimes it would work on startup, sometimes it wouldn't. Sometimes it stopped working while I was driving.
Replaced it and 4 years later no issues like that.

Unless you have a bad electrical connection somewhere, then it's almost certainly a bad regulator.

Coug said:

My regulator worked intermittently. Sometimes it would work on startup, sometimes it wouldn't. Sometimes it stopped working while I was driving.
Replaced it and 4 years later no issues like that.

Unless you have a bad electrical connection somewhere, then it's almost certainly a bad regulator.

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Thank you!

Before spending money on a new regulator do some troubleshooting, is there 24V at the IGN terminal on the reg when it is running but not charging?

Here is the manufacturer troubleshooting guide to verify the issue is the regulator so you aren't just throwing money at it

Check the ground wire for the voltmeter. Small possibility the regulator is fine and the meter or it’s connection is farked.

Also clean and retighten the connections to the regulator to ensure clean contacts.

Mogman said:

Before spending money on a new regulator do some troubleshooting, is there 24V at the IGN terminal on the reg when it is running but not charging?

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Thank you! I am unable to start it yet, as I just reinstalled the radiator and oil cooler and need to refill fluids when I have time. First have to jack up front end and turn wheels 40 times, lol. However, that is the very next thing I will do once that is done.

TOBASH said:

Check the ground wire for the voltmeter. Small possibility the regulator is fine and the meter or it’s connection is farked.

Also clean and retighten the connections to the regulator to ensure clean contacts.

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Yes, will do - thank you!

It’s clear in the pic that the AC and IGN wires have been spliced…I would verify the connections are intact.
if you have an over running pulley, make sure it’s also operating correctly

Retiredwarhorses said:

It’s clear in the pic that the AC and IGN wires have been spliced…I would verify the connections are intact.
if you have an over running pulley, make sure it’s also operating correctly

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Thank you - will do. I hope to get the assistance of my electrician son-in-law. My one concern was the clutch pulley. I have heard those can cause my issue - but I am unsure how to diagnose that. As I said in the opening, the generator pulley turns easily and smoothly by hand with the belt off - but I have no idea if that means anything re: the clutch.

Coug linked/ forwarded the TM tech manual. Have you read it?

OrangeElvis said:

Thank you - will do. I hope to get the assistance of my electrician son-in-law. My one concern was the clutch pulley. I have heard those can cause my issue - but I am unsure how to diagnose that. As I said in the opening, the generator pulley turns easily and smoothly by hand with the belt off - but I have no idea if that means anything re: the clutch.

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Clutched pulley should spin freely in one direction, and solidly turn the generator shaft in the other. Basically designed to the rotor can keep spinning when the RPMs drop or stop, without putting stress on the belt.
Or it may have a pulley without a clutch, in which case it will be solid to the shaft when turned in either direction.

TOBASH said:

Coug linked/ forwarded the TM tech manual. Have you read it?

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Yes, I printed it out and have read through it. However, I did not see anything about the clutch pulley - or perhaps that is broadly covered by the "alternator is defective"... I will take it with me when I go to my son-in-law's to test everything.

Coug said:

Clutched pulley should spin freely in one direction, and solidly turn the generator shaft in the other. Basically designed to the rotor can keep spinning when the RPMs drop or stop, without putting stress on the belt.
Or it may have a pulley without a clutch, in which case it will be solid to the shaft when turned in either direction.

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Can you tell by looking at this picture? Belt is back on so I can't try that now...

OrangeElvis said:

Can you tell by looking at this picture? Belt is back on so I can't try that now... View attachment 922459

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Yes that is the clutch type pulley, you can turn the fan on the rear of the alt, (with the engine off!!) it should only turn in one direction.

Mogman said:

Yes that is the clutch type pulley, you can turn the fan on the rear of the alt, (with the engine off!!) it should only turn in one direction.

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Great, thank you!