Hi Everyone,

I'm trying to figure out what is wrong with my truck. Initially it seemed like I had a dead battery. I had been listening to the radio for a couple of hours while I was cleaning my truck. I went to start it and it barely turned over and then clicked and all the gauges on the dash went haywire. Long story short, I ended up taking the truck to autozone to test the alternator/batteris since this issue happened again. They said batteris looked good, but that I had a failed voltage regulator. Looking on the forums here, I found the voltage regulator was built into the alternator (2006 F250 6.0). So I bought a new DC Power 185, installed it and the truck seemed to work great for awhile. Then I let the truck sit for a couple weeks, which I dont normally do, and tried to start it. It did, but barely had enough ummph to start the truck. I drove the truck for a bit, parked it and the next morning went to start it and it again barely had enough to start the truck. From past experience, I can tell when the trunk cranks over strong and when it sounds like theres not enough juice. So today, I take the truck to a different autozon, and again they show the batteries are good, and that it has a failed voltage regulator.

Some things to note:
-The batteries have a sticker on them that show they are only about 3yrs old, and are Duralast gold batteries
-I still have the OEM alternator that I plan to take in and have them test now that its off the truck

What do you think could be my issue?

Thanks in advance

 

I would have to question the batteries, if they aren't up to snuff they can take out an alternator. And 2 years is about the life span of batteries in these trucks due to the high demand put on them.

 

load test the batterys ,but would change them out before you toast the FICM from low voltage. Batterys are cheap and the FICM costs more. More likely the batterys might check good but voltage could drop down enough to harm FICM during high amp draw

 

Since the batteries were tested in the truck, and not individually, do you think that could throw off their tester? Also, would a bad battery(ies) give a failed voltage regulator error?

 

3 year old batteries that were on a poor performing alternator
= dead batteries. By under charging the batteries for a long
time they have lost the capacity and 3 years is good for a diesel.
Also look at all the truck side grounds and make sure that they
are clean and the cable is good.

Sean

 

Yes it could throw the test off if they were still connected together, and if the electrical system pulls alternator max rated amps for too long it will kill the diodes in the alternator.

 

Ok, so I will check my cables and grounds. Then I'm going to test the batteries individually, and the OEM alternator (now that its off the truck). Then I'll probably replace both batteries. If I'm still getting a failed voltage regulator then I guess that means I killed my brand new alternator?

 

If this is the case, do you think DC Power will cover under warranty? I just bought the alternator about a month ago i think.

 

One thing that's overlooked is the harness connector at the back of the alternator. They can and often do break right at the connector.

 

Thanks for all the input everyone, I really appreciate the advice. I'll check these items out when I get home