2003 Charging System Issues

Hammer

Hammer

Verbal Junk Author
Joined
Jul 3, 2006
Messages
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Let me first start with this mess hit yesterday out of the blue with no prior issues.

Truck charges normal then all of a sudden it drop the gauge off the scale and the check gauges light comes on and it throws codes related to the charging system errors.

Things we have done already while trying to sort this out.......
-Removed all battery cables and cleaned and checked them.
-Load tested both batteries and checked them for charge,both OK.
-Removed the alternator and had it checked and it tested fine at alternator shop.
-Checked all body grounds and removed them and cleaned them.
-Checked engine grounds and removed and cleaned them.
-Unhooked the grid heaters completely and no change.
-Main cable with fuseable link from alternator to right battery appears OK,but who knows and I haven't swapped it to see it thats the issues yet.Will do that tmmorrow.

Even with all we did today it still acts weird and drops the voltage off the scale and throws a "check Gauges" light.It acts like it has a load on it similar to the grids working before it looses its draw but something is definitely taking away the charge for some reason then.

The truck has 250K on it and had zero issues until this started yesterday on a attempted trip to go away.I am at a loss and ready to just take great enjoyment out of watching it burn to the ground,maybe then I would find the issue.

Any ideas or help are appreciated as this must be beyond me.......Andy
 
I had the exact same issue. I had to pull my tranny for a little work and after I put it back in, the problem went away. The only thing I can figure is a harness connection issue on the bellhousing. Check those and see what happens. Sorry I couldn't be more help as it was kind of a mystery fix
 
I drove the truck for almost 2 years like that FWIW. I kept getting a battery temp sensor code and I tried new sensors, cleaned all grounds and cables and a whole list of other stuff. The truck still charged and never gave me any trouble at all except for the ding when the check gauges light came on.
 
Matt...
I actually read your entire thread on your issues before I posted mine up.
I have checked all the connectors I can see and reach as of now and still no change.
Beginning to think it may be a front control module,fuse box or ECM issue but until I swap out the fuseable link tomorrow I will not say for sure.

It just started for no reason and has not stopped at all and has me frustrated beyond belief.Before the issue it was flying down the interstate with not a issue and running nice and smooth,then poof,no charging and the warning light.I could understand if there had been other intermittent issues but we had zero issues with this truck.I am not going to screw around long with this as we use this truck for our daily driving.If we can not figure it out I will just part it out and look for something else with lower mileage.I have a friend who had a 04 that did the same thing and it never got fixed so it got traded.

There are days when I wished I still had my 98 around and not bought a CR,today is one of them........Andy
 
I have read on here and other boards it can be an ECM related issue which will require a rebuild of the ECM or replace. Get a good scanner and see what the ECM is requesting the alternator to charge too. Also, check the positive crossover battery cable for corrosion. The ECM senses the voltage from the drivers side battery, the alternator charges to the passenger side battery.
 
Spooler...
We had a good scanner on it nd watched as the commanded voltage to the ECM dropped to 12.3 and lower.Already thought of the crossover cable today and checked it but a bomb just dropped and hit me now and something I over looked.Matt's issue he had was never found and it corrected itself after a trans job was done and it never reappeared.

On the older trucks we had an issue with the main battery cable that goes down to the starter being attached to the oil pan rail with a metal cable strap and some tape around it.Over the years of starting,use and engine torque the cables would wear and try and ground themselves after the insulation would wear through.On my old 98 I had this issue and never thought of it until now and am going to go check the path of the cable down to the starter in the AM.

Thats what I enjoy about this place,it makes you think and there are plenty of ideas that spark your brain.........andy
 
Did you check your engine off and running voltages at the battery. I believe the pdm/fcm tells the alternator when to.charge or not. No regulator built in.
 
andy-it is caused by the extra valves you now have and karma from the old red sport!!! jk. hope you figure it out, I know electrical gremlins are a migraine in themselves.
 
Had a truck doing this a couple years ago. Ended up being mild corosion on one of the ecm connectors. Can of contact cleaner and some dielectric grease fixed her up.

Sent from my DROID RAZR using Tapatalk 2
 
I actually replaced my fuse box with a new one in hopes that it would fix it and it didn't. It actually did fix a headlight issue that I was having so it wasn't a complete waste of money. What codes are you getting Andy?
 
Well,
After a couple days of exhaustive work checking and rechecking connections/grounds and charging system we have it fixed.

It seems that the alternator would short out and discharge once the engine bay got warm and while it was normal temp it would work just fine.Swapped the alternator with a new one and the truck has been fine ever since.

Picaso,THANKS I owe you one!.........Andy
 
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