My Battery light has started coming on intermittently. Seems to be more prevalent at higher RPMs which is strange.

Im going to start by replacing the Alternator. Any recommendations on good aftermarket ones ? I have read that the basic re manufactured ones from the auto part stores dont last long in these trucks.

Thanks in advance!

2005 Ford Excursion 6.0 L Diesel.

 

Before replacing it test the wiring harness that goes to it. I fought with an "alternator" issue for a long time before I found the harness was bad on my 7.3.

 

Yep, what John said. Go through all the wiring and ohm it all out. Test for voltage drops between the alternator and batteries. The little plug on the back of the alternator fails over time due to the heat cycles.

 

Yes, definitely get the cause of the issue corrected first. If you want/ or have to replace the alternator, I and many others have gone with the high outputs from DCPower https://www.dcpowerinc.com
They are great units that hold up well. Their website may show as sold out. Give them a call anyway or call the guys at FICM repair.com. They stock them
Good luck, let us know when you find the problem and if you replace the alternator

 

I ohmed out the large red wire to the battery and it was fine. Im not sure how to ohm out the other wires on the plug.

 

what number did you come up with when you checked resistance on the B+ wire? What is the voltage drop across it?

 

I would also stop driving it. I had a fire due to the alternator bearing going out. It started with the random battery light indicator that my wife failed to mention.

 

Classic symptom that happens when the alternator brushes are almost worn out. They start to float above the commutator contacts at higher RPMs and the alternator output drops turning on the light.

Time for a replacement alternator.

 

I had one that would trigger the light around 5,000 rpm. Took the truck on a road trip with many high speed passes, finally on the way home after 1,200 miles I was making a pass at 5K and the light did not go off after slowing down. Made it the last 50 miles home with everything electrical turned off that I could running on the battery..lucky!

 

Ok, to update you guys, ? I went to FCIMrepair, and ordered a 185 amp alternator. I installed it per directions (charging batteries prior to starting).

Now, the battery light is gone, however, im seeing another issue. The instructions say the alternator should be charging over 13.5 volts. Im seeing 11.8 at idle.

Any ideas here ? Do you guys think the Alternator may be bad ? The batteries are only a year old.

 

I also fought with battery and charging issues for a while before figuring it all out. My main issue was the pigtail going to the alternator. I finally figured it out because when the battery light came on I got under the hood with the truck running and jiggled the connection. While messing with it, you would hear hear changes in the idle from the extra load of the alternator kicking on and off. I went through 5 alternators, and a set of batteries before figuring that out. Once the pigtail was replaced, I switch the alternator and batteries one last time and have not had an issue in almost 2.5 years.

 

Did you replace the entire pig tail ? or just the plug itself ? Im not sure where the other end goes.

The new alternator came with a new pigtail, however it plugs into the existing one, then to the alternator.

 

You nailed it Twitchy, it was the damn pig tail, I cut it off, and spliced in a new one, now I have 14.5 volts charging at idle!

Thanks man!!

 

Reps given for closure and to Twitch, but go back and read posts #2 and 3.