It's weird that it will charge full field for a while.
I'm taking the plunge and replacing the alt. I think I have tried everything else!
Thanks Dave.

 

When you test the alt by disconnecting the field terms. do you just hook the wires directly to the alt where the field terms screwed into? What kind of voltage should i see? Guessing this also bypasses the voltage reg.

 

Yes. Voltage will shoot up when you full field the alt., you should have a carbon pile hooked to the battery or at least have all the lights on and the HVAC fan going full blast.

 

I was looking for a list of what the engine light codes mean and I came acroos this forum discussion. I am having the exact same problem with my truck at 216,000 miles. So did you replace the alternator? Did that fix the problem? Did the 1 2 4 1 5 5 go away after replacing the alternator?

Thanks,
Bryan

 

It was the alternator. It even checked out on the machine, but I eliminated everything else, and when I replaced it all the problems went away.

 

Mine too.... I've had similar problems like this in the past (which I forgot to mention to you) and discovered it was just the ground wire coming off the negative battery cable had worked its way loose. Not this time though. Alternator was toast.