[Skull101]

I've read through all the related threads and found no solution to my issue.

I have an 07' with the 6.7l motor. I an experiencing low voltage on my charging system. I changed the alternator out, three times actually. O'reilly was thinking they gave me a bad remanufactured one. The batteries are far from new but they took a charge and showed they were good, O'reilly charged both batteries for me, trying to help where they can.

All my battery wire connectors are tight and clean, but they are far from new and show signs of ware. I am not getting any charge from the alternator, it has failed the in truck tests several times. My two gauges are showing 11.4 down to 10.6 and then the check gauges light comes on and then the lightening bolt comes on. I have the regular dash gauge and the one on my Edge Insite CTS2 show the same voltage.


I have read plenty of posts to see that batteries, cables and alternator are possible causes. I have replaced the alternator, my batteries took a full charge and the cables look good. I have read that it could be a 140amp fuse for the alternator? Is there such a fuse in my 07 fuse box? If there is, can you share a photo? A shop wants to think it is an ECM issue, that's a $1500 repair on a maybe. They are still investigating at their pace.


Has anyone else had these issues and could share their repair with me? I would like to start with the least expensive possible solution first. I can replace all the battery cables from anywhere from $300 to $400, batteries are at least $150.00 each and the ECM is just ridiculous. I don't mind spending the money on parts if it does actually solve the problem.

 

[arpipeliner872]

Just replaced the ends on my cables. It would do similar things with different codes. Usually alternator charge to high. I had seen the crack on two ends. The one burnt a hole in battery and I ordered military terminals. With new batteries and ends. It’s going like it should. Saw where you have ordered cables but I am on the road and didn’t want to chase cables everywhere.

Didn’t see the other terminal with just a crack. But you can see the one it toasted.

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[Skull101]

I do have cracks in a couple of my terminal ends, but damn they are clean and tight on the posts. I didn't order new cables yet, I was planning on it.

Wouldn't the alternator show that it was charging even if the terminal ends are iffy?

I was getting 10.6 amps of charge and check gauges light came on with code for low voltage charge. I had both batteries charged, put them in and volts came up to a solid 12v and held.

Any ideas?

 

[El Pozzinator]

If you can ohm your cables, anything over 0.5 drop and the cable is internally corroded. Voltage drop should not be more than 1% per linear foot of cable (0.14-ish). We generally use the 0.5 number because it's usually the crossover cable which goes. If your cables, batteries, and alternator are testing good, check out the battery temp sensor under the driver side battery. It could be defaulting to a no-charge indication by telling the alternator that the batteries are overheating.

Also check your grounds. There's a bunch of them. Most common issues are the two directly connected to the batteries, which are strapped to the passenger fender by the hood strut and the driver front outside frame rail behind the fender liner. Also need to check out the grid heater relay, which if it sticks on will drain your batteries faster than any alternator could charge them.

Hope this helps...

 

[esquilax]

^^^What he said^^^x2 most electrical problems are usually the result of bad grounds or the guy that worked on it before you, I didn't read exactly how you tested the batteries(load tested individually?) Have you checked the charge straight off the alternator? I just picked up 2 batteries from Costco 212$ out the door btw.

 

[Skull101]

Update:

My shop have performed extensive tests on the alternator and the batteries. They said they have OHM tested the two wires coming from the ECM to the alternator and they are good. He even inserted two different wires in the wire ports where the alternator wires come from the ecm to bypass the wires all together. Still no signal to tell the alternator to charge.

They put the alternator on a bench charge and it was good, said they load tested the batteries and they were both fine. Powered the alternator up by an external power source??? and then he said the gauge went right up to 14.5v.


At this time the plan is to hook up an external voltage regulator like the old Doges to bypass the ECM all together. If that works, we will know that it is the ECM not telling the alternator to charge. I don't have $1500 to put into a remanufactured ECM right now.

I will keep everyone posted. At some point I do plan on replacing my battery cables. Just not sure if I want to go with OEM ones for $380 or an aftermarket set from Custom Battery Cables with the military style terminal ends for $306. I'm just not sure about the crimped style cable ends on the aftermarket ones.

 

[arpipeliner872]

Not trying to sound like a smart but are you clearing the codes after you try something. Mine wouldn’t till I did cause I forgot once.

For me the truck ran fine going to work. Had to move it to back in and on crank up it showed check gauges and lighting bolt. I knew both terminals had cracks near the bolt area. This is the battery I hooked the drag tank fuel pump. It had been that way for over a year. They were tight and clean but one day it over charged and melted a hole in the battery.

I ordered the new terminals from amazon. Wish it had the bigger ends not to trim so the cables would fit in easier. I solder and squeeze with channel locks. Cost about $70. After installing the new batteries with old terminals the positive side was really warm to the touch but it made it to the campground before popping up the code.

Just trying to help. Don’t know if terminals will fix your problem but it’s a cheaper place to start. I had to from the picture. I am working 12 hrs a day and usually 7 days a week. I might get new cables later but I have a wheel bearing on the way out so getting the parts and tools for it now.
I used a dremmel tool to cut cables and insulation. Would have been a lot easier if I removed the battery.


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[Skull101]

Yes Sir. Cleared all the codes every time.

Update:

We tried the external voltage regulator. It charged alright, upon accelerating it was over charging. Going from 15,17, 18. Had to shut it off before we cooked the batteries. I don't know why it wouldn't regulate the voltage? It is a voltage regulator. It doesn't have a dial to turn it down.


We unhooked the external voltage regulator and hooked up the stock wiring. I got in the truck, cranked it up and it was holding firm at 12.0 on my gauges. I drove home, 28 miles and a little over 35minutes. I had the air conditioning on high, 95 degrees in NC. The gauge didn't move, either of them. Stock instrument panel gauge or the Edge Insight CTS2 voltage gauge. Holding firm at 12.0. Why wouldn't it drop a little if the alternator wasn't doing anything?


I have checked all the body and engine block grounds all clean and tight. I ordered Custom battery Cables overnighted and will install new batteries tomorrow. I will replace the battery temperature sensor tomorrow as well. I am just finding it hard to believe that my ECM would just decide to stop sending signal to my alternator to charge. No other issues with the ECM at all.

Ant thoughts?

 

[El Pozzinator]

but the alternator is suddenly charging properly?

if so, that sounds to me like whatever you and/or your shop did somewhere fixed the voltage fluctuation issue. the ECMs in these trucks are extremely sensitive to input voltage fluctuations - hitting a bump with a loose battery terminal will pop typically a 4-code combination of about 8 different codes, depending on what else the truck is doing at the time.

last one i had, i can only assume i must've left something a bit loose when installing a tuned TCM and the truck popped two voltage codes and two transmission codes. prior to that, when doing some suspension stuff i must've knocked loose a ground somewhere and the truck popped one voltage code, a MAF code, and two emissions codes.

which set of cables did you go with? if you went with those 2/0 custom cables (genos has them in stock now), i think you'll find your truck will be starting better with the bigger gauge cables. i sorta halfway want mine to crap out enough to justify dropping the scratch on a set of those things, or having a set of 4/0 marine cables made somewhere local.

 

[Skull101]

I dont think it's still right. It's only showing 12.0. Needs to be charging at 14.5 , I believe.

I went with the Custom Battery Cable . Com set. Company out of Arizona, set is made up exactly like stock set. Uses the military style terminals.

 

[jamvo]

The stock battery cables are crap and do cause some weird stuff to happen. You could’ve built your own out of welding cable and bought a crimper/smasher and probably be money ahead and had a new tool. Either way I don’t think you’ve wasted any money changing the cables.

You could build a new alternator charging wire out of #4 welding cable, it wouldn’t hurt but probably won’t fix your issue.

I think your issue is in the wiring that excites the alternator.

 

[Skull101]

Update:

I changed all the battery cables with CustomBatteryCables.com kit, new batteries that were tested and a new battery temp sensor. I cleaned up all the ground locations with a steel truck and have ruled out any other electrical issue I can think of.

It looks like I need a new ECM for this truck. Still showing 12.0v solid. I haven't driven it much since, I'm sure that is just the batteries.

I can't believe that all the things this ECM controls, it just decides to stop sending signal to the alternator.

 

[Skull101]

I had my ECM tested by a reputable company that tests and repairs ECM's. They said that there was nothing wrong with my computer, especially looked at the charging system.

WTH is the matter with this truck. It still shows 12.0v on the gauges and the alternator is showing a charge of constant 12.18 volts. It is still to low. It is supposed to be at least 14v?

 

[mindwreck]

yes. 13.7-14.5 volts is what most automotive batteries like to be at when charging and floating in normal temperatures. Anyone around you have a DC amperage clamp meter? See what kind of amps the alternators actually putting out. 12.18 is way low. What are the voltages of the batteries at every point.: truck off. truck off but keyed on acc. truck running but everything off(radio, lights, etc).. Any mods to yoru truck? any codes? BIG subwoofers you didn't know you had?

Also What do you mean by "Powered the alternator up by an external power source??? and then he said the gauge went right up to 14.5v." Only way that works is with an external regulator, which you said didn't exactly work.

With everything either brand new or tested fine.. Another scenario is the ECM is not seeing the true system voltage, so its thinking that the batteries are charged and its telling the alternator not to produce more current. ORRR the ecm is telling it to and the alternator just doesn't want to do its job. Either way, somethings not on the same page. typically its the other way around, ecm thinks the batteries are low because of corroded wires and overcharges the batteries. Odd thing is you've been driving it and its not dying and its still starting up just fine? Which the alternator is still providing power to keep the truck running..


Okay so I've been thinking about this post for last 20 minutes. ANOTHER THING is Starting the truck and having them sag all the way down to low 12v even 11 vmeans theres a HUGE load keeping the batteries that low.. a load such as a grid heater is stuck on( i think 200 amps?? ) .. could try pulling the power to that. I've seen that issue before..

 

[esquilax]

Are you 100% on the condition of the batteries, seems like you have been having someone else work on it, are you getting your readings from onboard gauges and not with a multi meter a battery with 12 volts can still be junk, you have been starting and driving okay right? Still throwing any codes?I'm still leaning towards a poor ground or connection somewhere, unless it's the batteries.new alternator,cables cleaned,you said the ecm checked out? Electrical problems can be a real pita, be patient and do the work yourself and you will have that AH HA momen,

 

[esquilax]

Powered the alternator up by an external power source??? Back when I worked in an auto parts store (a long time ago) we had an apperattes to mount alternators,generators and starters into for testing I have seen one of those in a long time

 

[jamvo]

I second the grid heater comment. The grid heater cycling taxes the crap out of the charging system. The wiring for it on the passenger side near the battery is suspect too. You could disconnect it from the battery and see what happens.

 

[El Pozzinator]

From what I've read when the grid heater relay craps the bed it usually defaults to an "on" condition. Disconnecting it you'll pop a code for it, but it should still run just fine until it gets really cold out - then it'll lope like a 3-legged horse until it warms up. Block heater helps with that though...

 

[Skull101]

Thanks for all the input guys. I have a grid heater delete kit on the truck. I did that when I had a Gen II turbo upgrade installed and the Banks Monster intake.

I'm at a loss for what this issue could be. I have an appointment with the dealer on Monday, I will insist that they put their best electrical person on it. I will pay the diagnostic fee and see if they can find a cure for the issue.

I have done all the work and replaced all the parts that I could myself before taking it to a dealer.

 

[steadly2004]

Thanks for all the input guys. I have a grid heater delete kit on the truck. I did that when I had a Gen II turbo upgrade installed and the Banks Monster intake.

I'm at a loss for what this issue could be. I have an appointment with the dealer on Monday, I will insist that they put their best electrical person on it. I will pay the diagnostic fee and see if they can find a cure for the issue.

I have done all the work and replaced all the parts that I could myself before taking it to a dealer.

I had this (very very similar, alternator would put out like 10-11v) issue with a previous vehicle. I even replaced the starter 2-3 time and the alternator 2-3 times from different stores. It took me almost 2 years to figure it out and I still don't know how the wire got jacked.


Turned out the alternator had more than one wire connected to it and the wire that tells the alternator to function and generate electricity was crimped somewhere. It's a voltage read wire, and was seeing 6v when the system had 12-14 on a new battery. I had to run a new wire from the alternator to the alternate power source read directly since I couldn't find the damage to the wire within the harness. Have you looked at the connector (whatever connects to the alternator that's not power/ground) and followed those wires? I didn't believe it was something that could cause this. I thought the alternator generated electricity when spinning no matter what was on the connector. But I was wrong.