I swapped in 2-145A alts, on my dual alt settup. The old 105's removed. I get 14.3V at idle with the battery light on, and DIC message "battery not charging". The light goes out over 1400 rpm. Surely 14.3 V is more than enough to kill that circuit? I assume it is a voltage measurement that triggers the light.

Despite my best efforts, I shorted the battery block when disconnecting the system. May have something to do with it.

I plan to upgrade the wiring to 4 or 2 gauge at some point, don't see how that could be the problem.

What is the voltage @ 1400 rpm?

What voltage do you get over 1400 rpm?

My foot won't reach that far?

But the gauge doesn't move almost at all. Stays at 14.2-14.5 best guess

The 14.3 above is avoltmeter measurement across the batteries

Use your jumper cables to bring battery voltage to the drivers door. (Makes your legs longer, LOL)

Check fuses KB. If you have a trouble light check them all. May just be a DIC problem

I'll do that when I have some daylight.

Eric, where are you?

I plan to upgrade the wiring to 4 or 2 gauge at some point, don't see how that could be the problem.

Battery cables should be 2 gauge, OEM. 1/0 would be next size up. I plane to go to 1/0 or 2/0 my self.

FWIW.

I was referring to the alt feed cable. Looks like maybe 8 awg.

14 left, 4 right.

Despite my best efforts, I shorted the battery block when disconnecting the system. May have something to do with it.

It sounds to me like you have damged the fusible link between the alternator and the battery (the charge lead). You should get out a multimeter, flip it to ohms, and measure between the end that connects to the alternator and to the battery (it doesnt matter which one because they are in parallel) If you have over a few ohms then you could have a problem. If you have over 20, or 40 then you absolutely have a problem.

The short you mentioned earlier could have just damaged the cable, making high resistance which would make the computer not see the batteries charge, but once the alternator starts cranking out more amperage (at higher rpm) it is probably sending enough juice to make the computer register. Also, the high output alternators could have enough power to damage the factory fusible link just under normal duty because they can put out more than the link is rated for. Even if this isnt the fix, you should change the cable out.

Checked all fuses on th dr side. Found 2 hdlp cb's blown, which answered my headlight issue (another story).

The only fusible link is on the wire from the no 1 alt to the battery block. That wire checks at .1 ohm motor off, 2.2 Ohm running. The battery cables have no links I can find.

Still stumped. The weird thing to me is, either one of these should be able to power the system alone. Time to check for codes.

Are the Dual Alts factory installed?
Are the present Alts OEM?
Was the engine running when the short occurred

If the Alts were added or changed post OE, they may be ReMans.

Do you hava a clamp-on amp meter?

No codes

Pulled the 4 pin connectors on each alt. Showed discharging state, about 10 V, light on. Expected

Plugged in number 1 alt. Shows charge, light out

Unplugged number 1 alt, plugged in number 2, shows same charge (14.5v), light on

Totally baffling. FYI, the number one alt connector has 2 wires, the number 2 alt has just one.

Are the Dual Alts factory installed?
Are the present Alts OEM?

If the Alts were added or changed post OE, they may be ReMans.

Do you hava a clamp-on amp meter?

Factory duals, these are both new, but each comes from a different source. The one that is throwing the light came from Checker (a place I hate). I wonder if there could be a diiferent TR in some of these that is a compatability issue.

Disconnect one alt and check operations.

Try each alt by its self.

see post above Fox

Will this help? It for the '03.

http://img137.imageshack.us/img137/6792/dualalts8is.jpg

LOL

You have me confused with Fingers

Actually, that is my system. Nothing there that helps me understand why a 14.3 V signal should illuminiate a DIC warning.

I will get another alt I guess and try that in the right (#2) location.

Alt 1 and Alt 2 plugged in but bat connection for Alt 2 opened?

KB,

I would suspect that you probably have a defective voltage regulator in the number 2 alternator. Put one of the 105's bac in place of the 145 #2 and see if your problem goes away. If it does...take it back.

John

Ya you may have 1 bad alternator.

The good one is keeping voltage normal but the computer is seeing that the other one is bad.

Just a thought.

DD

.

Thanks for the help guys. I will swap out the #2 alt. Right now running on the one. I will up the wiring on these as well to 4 gauge (bit of a compromise, should be ok to move 100 amps each, only 1 foot length).

As shown in the diagram, number 1 has a fusible link. No. 2 alt does not. Anyone know why? Does the one protect both? Is it necessary to add it?

Also, I really would like a better battery "junction block"? Accessorizing! Any ideas?

LOL

You have me confused with Fingers

I HOPE that isn't the case. :)

The goto man for a circuit question. I am afraid of electrons!

Yes, but; did you Fix your truck ??????

waiting on the new alt. works for now

The new alt (same as number 1 now, identical) has no issue. Not sure if there was some ac phase difference or what. This one charges just the same. But no msg.

Fixed, but I don't know why.

I spoke too soon. The problem is exactly the same with the new alt.

Summary:

Each alt will charge, by itself (gauge=14.5), no lights.
With both plugged in, I get the lights, this time instead of under 1500 rpm, I get it under 2000 rpm.

This is driving me crazy.

so you had dual alts from the factory? and just upgraded to 145's?

Damn I'm cornfused why that would cause any problems. Unless your somehow back feeding the alts.

so you had dual alts from the factory? and just upgraded to 145's?

.

right.

Is there a special alt for a dual alt configuration?

I wouldn't think so. Have you tried to ask the stealer??? Just curious if you were over charging the system. :banghead:

14.5 V staedy (oem gauge). DIC goes off over 2000 rpm. If overcharging it would be worse at higher rpm.

All this with no real electrical load.

wonder what a tech 2 would show, or any other kind of obdII scanner.

so you can run a single alt either size 105 or 145 and it's ok, you can run both 105's and it's ok, but when you run both 145's your get that goofy light?

so you can run a single alt either size 105 or 145 and it's ok, you can run both 105's and it's ok, but when you run both 145's your get that goofy light?

Close.

Only the number 2, 145a alt triggers the light when the plug is connected.

Something you said made me go check something. The 145 is physically bigger, and install is a squeeze. I noticed the alt postitioned, such that, the alt juice terminal, although booted, rests a few microns from the "ground" strap. I pulled the ground strap away,

A proximity short?

edit: Problem still there. For some reason, when I stand out side the truck and start it, the light goes out. Till I get in and go drive.

This is tricky.

After a long ride, I get the light less than 10% of the time, very intermittent, no rhyme or reason or pattern.. Doesn't follow RPM now at all. Just random.

The #2, offending alt was 15-20 degrees hotter than the #1, 130 degrees, very toasty, hotter than the motor bay.

I also notice the chassis seems hot (+V). I am getting all kinds of stray sensations.

Have others installed dual 145s? I've heard of dual 130's.

The ECM controls the charging rate of each alternator.
Generator Left is primary, and Gen Right is secondary. At idle, the 145's must put out >70amps, (the 130's @ idle are rated at 67 amps @ idle).
If each 145 alternator is putting out at least 70 amps at idle, and the electrical load at idle is low, could the ECM be trying to shutdown alternator 1 so low, that the ECM senses this low output as a failure? If so, maybe dual 105’s or 130’s would work better.

Maybe primary Generator Left is bad. Did you try replacing it with a spare?

Is the ECM sensing current or voltage at pin B? Measuring 14.5 volts may tell you nothing if the ECM is monitoring current.

Looking at idahofox’s schematic at post #19, the Charge Indicator in the ECM does not monitor Generator Right’s output. That would explain why disconnecting Gen Right wire harness would cause a Low Voltage sensed by the ECM.
Have you checked pin B at Generator Left, (Charge Indicator Control), for proper connection?

If Gen #2 is 15-20 deg hotter that Gen #1, to me that's saying that Gen #1 aint puttin out.
The way I understand it, Gen #2 doesn't load much until Gen #1 gets loaded heavy.

When the plug for each generator is pulled, the voltage is 14.5, IOW, each provides rated voltage

Both alts are brand new.

I took volatge readings from the case of each alt to the battery + terminal, it turned the voltage indicator squirly, could not even get a reading. I was expecting 14 V.


Electric stuff is out of my realm somewhat. Thank you for the help.

swap the alts with each other. Just swap the two 145's if the temperature thing follows that alt, then I would say that alt is still jacked up.

Hopefully that isn't too confusing.

electrical problems can be a huge pain in the ass to figure out.

It sounds to me like you have damged the fusible link between the alternator and the battery (the charge lead). You should get out a multimeter, flip it to ohms, and measure between the end that connects to the alternator and to the battery (it doesnt matter which one because they are in parallel) If you have over a few ohms then you could have a problem. If you have over 20, or 40 then you absolutely have a problem.

The short you mentioned earlier could have just damaged the cable, making high resistance which would make the computer not see the batteries charge, but once the alternator starts cranking out more amperage (at higher rpm) it is probably sending enough juice to make the computer register. Also, the high output alternators could have enough power to damage the factory fusible link just under normal duty because they can put out more than the link is rated for. Even if this isnt the fix, you should change the cable out.

Dummy me. You gave great advice. Me, the walking lightning rod, I never measured the #2 juice wire from the alt, or it was unplugged. It was at 43 Ohm

The number 1 was at 6-8 ohm.

So the #2 alt wire is like 6" long and has "8" printed all over it with the words "fusible link". Is that 8 ohm? I didn't know a wire itself could be the fusible link.

Where do I get 4 gauge fusible link wire.?

Update: Checked the loads of each alt.

Since I changed out the 105's for 145's (backup home generator project), I have had a DIC warning, "battery not charging" . It is intermittent. I got the ammeter out after thinking a bit. Here is what I discovered

1. Load after starting is about 50 amps
2. If #2 plug is removed, DIC stays off, load is handled by #1
3. If #2 is plugged back in, all load transfers to #2, and #1 goes to about zero, and DIC is intermittent.
4. If #1 is unplugged, DIC comes on continuous, though all load is handled by #2.


Strange. I believe #1 is suppose to handle all load in dual alt settup. What is causing the shift to #2?

Will this help? It for the '03.

http://img137.imageshack.us/img137/6792/dualalts8is.jpg

I had thought that Generator Right, was the primary, and Generator Left was the Secondary Generator.
If you look at Gen Left, terminal C is connected to ECM C2-52, labeled Gen Field Duty Cycle Signal. Looking at Gen Right, terminal C is not connected to anything. I'm looking at my 2002 Helms schematics, and they are drawn the same.
Did they forget to add the Terminal C wire to Gen Right on the schematics? Doesn't each generator need a control signal to tell it how much to load to?
My 2002 Helms schematics show the single Generator wired like the Gen LeftHope it's not too small to read, I had to shrink it.
Attached Thumbnails

If the Gen Right truely is the primary, and it has no loading signal wire from ECM at terminal C, maybe that explains why it isn't loading, stays cool, and you get a fault signal, and Gen Left is picking up the load as designed.
Others on this site have done this mod. What directions or schematics have they used?

Gen Right is the "extra" in the dual alt settup. What I referred to as #2. Notice it is single wire.

It is not a mod per say. My truck was born with duals. All I did was swap alts and pulleys are equally undersized..

I suspect the DIC warning is due to low/no output on the left, the only one monitored I will guess.

In my 2002 Helms manual, page 6-1603, it says with dual Gens, Gen 1 is Right, (Passenger side), and Gen 2 in Left, (driver side).

My schematics are labeled different than one above.
For Gen Left, Term B to ECM C2-15 is labeled "Charge Indicator Control".
For Gen Right, Term B to ECM C1-32 is labeled "Charge Indicator Control".
ECM C1-32 is not labeled "Generator 2 Turn On Signal", as shown above.
It would seem to me that Term B on either Gen in monitoring load, and Term C should be controlling the load.
Again, drawing above has now control wire at Gen Right, Term C.
Maybe there's something I don't understand.

One more thought, you said your truck was born with dual alternators.
With the 01/02's, the 105A or 130A were the only options. My manuals does not specify any difference on electrical plug pin configuration.
Could the pin configuration in the 145A Generator be different than the 105A/130A Generators?

I know that the pass side alt is primary, the one everyone has. It also had the fusible link shown. The secondary "extra" alt is driver side. Shown above as "gen right". It had fusible link wire, 8 gauge. Both wires have been replaced with 4 gauge, no fusible link. (the problem existed before replacing those cables)

Thanks for helping

Could the pin configuration in the 145A Generator be different than the 105A/130A Generators?


hmmmm

killerbee,

You're not alone:
http://dieselplace.com/forum/showthread.php?t=61107