Hi All,
New guy here, so hi to everyone.
Hopefully someone here has encountered this problem or knows someone who has had it and maybe has the knowledge on how I can fix it.
So here it is. I went to start the truck this morning and it turned over like usual except at the very end before starting it kind of lugged a little bit like a low battery.
So the truck started and I looked at the volts and the needle was pegged to the left -9. The motor was running fine. So I thought ok I'll just turn it off and restart
see if that fixes it for some odd reason. Well I started it and it ran for about 1 or 2 seconds and shut off. Now when I try to start it she just starts for a second or two
and shuts down. Both batteries read 12V when tested. So if anyone has any ideas please share and thanks much.
Forgot to list what it is.
2005 Silverado 2500HD
6.6 Duramax LLY
Allison Trans
4x4

Bush

 

check the batteries first
12 volts.....12.0 volts is a dead battery. 12.6 volts is a fully charged battery. you have dual batteries so they must be isolated from each other to test or it will read as one big battery.

multiple ways to test a battery....conductance testing is fast and easy. load testing with a carbon pile or by engine cranking test but the batteries must be fully charged first.

if you fully charge the batteries and the truck starts...measure the voltage at the battery...with the engine running it should be between 13.5 to 15.5. if its reading under that the charging system isn't working. Is the battery light on or cel light on...check for codes.