alternator question

This one is mostly for CUCVRus.
The previous owner spliced the wire from the driver side alternator (I assume it's the exciter wire) and ran a bypass to the pass side alternator and cut the black wire , which originally went to that alternator.
I want to take that splice off and see what Issue I am going to find unattended. I assume that one alternator needs to be rebuild and just doesn't put out enough voltage and that someone tied both together.
But I am not sure.
What is your thought on why someone did this change in wiring?

OBTW; reason whyI am doing this is that I have the sneaky suspicion that the the charge system does not put out enough charging power. And i like things to be the way they have been intended to be.

Correction:
It's a brown wire not a black wire
driver side


passenger side

I am clueless. Looks like some hack job to me. I have no idea why they done it. Do both Gen 1 and Gen 2 lights work?

The picture of the alternator plug shows the crimp splice is on the #1 regulator terminal. That is the exciter terminal and turns on the regulator. I don't think you can tie alternator #1 and #2 together this way on the original isolated ground system. Does the other end of the jumper go to terminal #1 on the drivers side alternator?

Do you know if the truck is converted to 12 volts for the starter and glow plugs?

cucvrus said:

I am clueless. Looks like some hack job to me. I have no idea why they done it. Do both Gen 1 and Gen 2 lights work?

Click to expand...

I see the gen 1 light come on when I start her and the rpm hasn't exited the alternator yet. When i raise the engine rpm a little it gors and stays off.
So I know the gen 1 light works. Not sure about gen 2, ill see what will happen once I return it to normal.

I'm with tow4. First verify it's still 24v, then go from there. I"m guessing something wasn't workings, and a hack job was how the PO 'solved' the problem.

I take it you want to put it back stock and troubleshoot from there? If so, I think you are going the right direction. Trying to unravel someone else's hack job is just going to be frustrating. You'll be trying to guess how someone misunderstood the system. Rots a ruck with that!

Looks to me that Alt2 lost it's exciter circuit, so he tapped Alt 1 circuit to excite #2.also.
Providing the Gen 1 light on the dash works, and Gen 2 doesn't.
After you unhook that mess trouble shoot Alt 2 circuit.

Tom

MarcusOReallyus said:

I'm with tow4. First verify it's still 24v, then go from there. I"m guessing something wasn't workings, and a hack job was how the PO 'solved' the problem.

I take it you want to put it back stock and troubleshoot from there? If so, I think you are going the right direction. Trying to unravel someone else's hack job is just going to be frustrating. You'll be trying to guess how someone misunderstood the system. Rots a ruck with that!

Click to expand...

I know the truck is 24v. But CUCVRus is right the wire didn't make sense and when I cut it out and placed it back exactly nothing happened. Just started like normal

TGP (IL) said:

Looks to me that Alt2 lost it's exciter circuit, so he tapped Alt 1 circuit to excite #2.also.
Providing the Gen 1 light on the dash works, and Gen 2 doesn't.
After you unhook that mess trouble shoot Alt 2 circuit.

Tom

Click to expand...

Tom after reading your post, I'll go out there and check if both alternators charge as they are supposed to at the battery.
So here it is:
Gen 1 charges 14,53v at the front battery
Gen 2 charges 12,6xV at the rear battery

I think the Gen 2 voltage regulator is toast. If I measure from the alt plus to ground, I get 27v. If I measure from alt plus to battery ground I get 12,5v

12.6V at rear battery shows Alt 2 is not charging or Very little.
It's normal to see 24+volts at the output stud of Alt 2.
Even though it's a 12V Alt you will have 24+ volts there.
That's where the Isolated ground comes into play and makes
It so hard for people to wrap there head around this system.

Troubleshoot the Alt.2 plug and see if you have 12v there.
I bet the small brown wire is dead.
If you have no Gen2 light with Ign. on there is were your problem is.

Use the TM to trouble shoot the system.
Tom

Gen 2 is not charging. Not even a little.

what is the 'alt 2 plug'?
I don't have a gen 2 light with Ign.on. So where is my problem?

Also I don't see the capacitor on the Pass Gen. I have it on my M1009 but not on the M1028.

The plug I'm referring to is the plug at the Alt with two small wires,
Where the PO tapped.
The missing capacitor has nothing to do with it not charging.
It's only for radio interference.


Could be numerous reason why Gen 2 don't light.

Problem with bulb or socket, wiring,Gen2 relay, fuse, etc.
That's why you need to read and study, then follow the troubleshoot tree in the
TM

Tom

TGP (IL) said:

The plug I'm referring to is the plug at the Alt with two small wires,
Where the PO tapped.
The missing capacitor has nothing to do with it not charging.
It's only for radio interference.


Could be numerous reason why Gen 2 don't light.

Problem with bulb or socket, wiring,Gen2 relay, fuse, etc.
That's why you need to read and study, then follow the troubleshoot tree in the
TM

Tom

Click to expand...

And have a multi-meter.

porkysplace said:

And have a multi-meter.

Click to expand...

always have a multimeter

Test alternator #2 on the truck with the engine running by running a jumper wire from the alternator's B+ terminal to regulator terminal #1. This will turn on the regulator and the alternator will charge if it works.

So I checked the lightbulb and it was ok
I cleaned the lightbulb holder with my fiber glass pencil and put grease on it.
I swapped the voltmeter repay for the Gen 2 relay and the voltmeter still worked.
I cleaned the Relay contacts with the fiberglass pencil and put grease on the contacts.
I checked the 10 amp fuse again, but I knew it was working. (I have these LED fuses that light up, if they are blown)

Ign.on had gen 2 light.
Start truck Gen 1 charging , Gen 2 charging

Odd. Covering the basics does it again. Funny how that works.

I believe it had a bad connection at the lightbulb, either the bulb itself or the holder. I looked at the Schematics and it looks like the Gen 2 wouldn't charge with the bulb not working (making good contact).

Correct.
Along with the proper bulb.
Gen two light is #194
All the rest are #168

Well Done!
Tom