I am new to this site and had some questions regarding my truck. I had done some searches on the web but I keep coming across sites that are quite a few years old.
The batteries keep dying. I can charge the batteries and drive it to work a couple of days and by the fourth day, it's dead again. Have replaced alternator, batteries, and starter and I am still having issues. Just noticed this weekend, the instrument cluster going off, coming back on, shutting off again all while the truck had been running for about an hour. I'm not sure if it is because the battery was dying or what. As soon as we got home after the instrument cluster incident, turned the truck off and tried to start it. The battery was completely​ dead. Anybody else having this issue or had it in the past? Any suggestion's will be appreciated.
I have been looking up on sites and I keep coming across the GEM Module. I want to ask around before I buy it. I have also noticed small issues with my 2000 Excursion. Back windshield wiper starts up upon the vehicle starting. Goes a few times and stops. Not sure if this is the same type of issue as in the GEM Module.
Thank you,
Art Martinez

2002 Ford F350 7.3l Diesel with 148000 miles

 

I assume you tested the alternator before (and after) you replaced it? It's possible you got a bad "new" alternator. Maybe change out the alternator cables. Something's obviously killing your new batteries and the culprit is usually alternator related. Figure just double check that simple stuff first.

 

I did test the new alternator after it was installed and it was putting out 13.7 volts. Not sure it is the alternator. The batter will go from full charge to 5% in the 9 hours I am work. This will happen after two or three days. It starts just fine in the morning but it will be dead in the afternoon.

 

I think the alternator should be putting out about 14.5 or so when running.

Check/replace the alternator cables.

 

Parasitic Drain? Did you pull your fuses to see if the drain stops?