I put LS1 fans on my 04 Sierra yesterday, used a Blackbear Harness. Yesterday everything was fine. This moring the battery light and a message that says "Battery Not Charging" comes on for a few seconds then goes off, then comes back on. Checked the alt wit ha volt meter, it puts out 14 volts then drops then comes back to 14. Gaudge in the truck never moves, drove it work without an issue. Any ideas?

 

No ideas yet? Could i be the alternator? I did have the PCM out to put the pins in for the fans.... any ideas? I needs some help guys!

 

Did you search...guys talk about going to a higher-output alternator and/or doing cable changes to lessen the load on the alternator. You can get the alternator checked for free at a lot of auto parts stores.

How far down from 14 volts did it go? Generally,about 13.8v to 15.5v is considered normal charging voltage.

 

This thing is confusing the hell out of me now! I hit a bump earlier and it worked fine for about an hour. Got home and and checked it and the alt isn't putting out anything. So I'm guessing it's coincidental that alt has given up at the same time I put my fans on. Anyone else have any input?