Battery light now dead batteries dual alt's

[ZF5]

2008 f350 6.4 had battery light on for some time now and now the batteries wont stay charged. The lights are bright and when i drive it every day it does ok. However my battery light stays on and i see i have dual alternators. Thers a chirping noise coming from what seems the upper alternator. It looks like a COMPLETE NIGHTMARE to change... how bad is it?? I dont want to spend 300 dollars on the wrong one so im guessing the squeeky wheel gets the greese to say? Should the bat light go off after i replace it? Idk if there both bad because if i keep driving it it seems ok but obviously does not have the charge it shouldnt. Previous 7.3 guy so bare with me! Haha

[bag711]

Test ur alternators with a volt meter and replace one if its putting out to low or high of a voltage. And since your batteries have been drained of power a few times their not gonna last long now might aswell swap those out.


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[K1LLsW1TchEd]

Yea that's bad news if you drained the batteries a few times and the alternator wasn't functioning properly. I would replace the alternator and batteries.

[Doss]

Make sure the alternators and batteries have good cables. I had the same thing happen on one of my cars and took forever to track it down. The cable on the back of the alternator had corroded and the stud it was mounted to was broken. The only reason the wire stayed attached was because it was heavier gauge and stiff.

I'd bring it to a dealership or some place that can test dual batteries/alternators.

[ZF5]

Alrighty guys got an update... I fired up the truck as i drive it rarely... its about 10 degrees and they needed a charge to start the truck. I put a multimeter on the batteries and was a little shocked by what i found! It was putting out 22 VOLTS!!! I had about the same amount of voltage on each alternator post. Where in the world do i go from here. According to a young punk at advance auto lol he said i need to change both batteries and both alternators, i kinda laughed he priced the alterernators they were 450 and batteries were 250 so 700 dollars and MAYBE???? itll fix it idk about that jazz... any advice or anyone EVER have this issue?? Overcharging seems like some regulation issue. Its pcm controlled i think so maybe one is bad or maybe the batteries are shot. look to be maybe original motorcraft batteries but show green on the indicator. Woa is me....

[Doss]

You need to test the alternators and batteries individually off the vehicle. If the alternator is bad, it can produce too many volts. This problem usually is a faulty voltage regulator, short, bad wires, etc. This can cook the batteries as well and lead to failure. It could also lead to failure of sensors and other electrical components.

Remove the parts and have them tested at an auto parts store independently.

[ZF5]

I had the alternators tested. The top wouldnt take a ground on the machine. The lower tested good at 14.3 volts. The upper wouldnt even test. Im replacing it. It has a really noisy bearing anyways. Also i have to apparently replace the batteries as they could have an internal short causing the regulator to go crazy. I also have a SCT programmer and idk if that has something to do with it or not... also are EGR deletes still availible???

[K1LLsW1TchEd]

Plenty of deletes available