Battery went completly dead after setting overnight. Installed new battery and will start but only returning 11.8 volts when running. Pulled alternator and it checked out fine along with brushes. Still only returning 11.8 volts to battery when running. What could I be missing?

 

Type in: RE: Hummer H2 Battery Drain, in the search box, this was posted by Mad Professor in 2007.

Quick check..There is a fuse box under the hood near the battery. There is a fuse in there that will prevent the alternator from charging if it is blown, so you should check that first...

This is how I usually check if my alternator is unservicable..start the vehicle..remove the battery cables..if it continues to run..the alternator is fine..by the way, this is also a field expediate way to "jump start another car whose battery died" if you don't have jumper cables available...just for thoughts.

Dan

 

IF,If the generator is actually good,then the controller or the ecm is bad.(or fuses)
The volts should go to 15 for a while,then about 14.
On new cars its never good to pull the cables when running.