Bought a 08 suburban for my wife. Drove it home, she ran battery dead, had to get new one bc that one had a bad cell. No start, no headlights or dome lights, only thing that worked was dash lights.guages didn’t do the run around they usually do. Tested all starting fuses,voltage reads 11.77, tested new battery,new starter new neutral safety switch, (you can see the PRNDL but no square indicator around it) checked lock cylinder and ignition switch thinking that was the issue, all good. Checked grounds on for wall and checked terminals as well. Checked MEGA fuse, good. At this point I want to burn the truck down. Any other ideas what it could be? Once again, turn the key radio n dash works, windows too, but no headlights,no door lights when u open door,no dome lights in general, literally nothing works like it’s dead but everything checks out. Called 3 buddies that work at Cadillac and Chevy store they’re stumped unless they see it but we can’t drive it anywhere.

 

11.8V is too low. Maybe it's not charging so get your alternator load tested at the parts store.

 

Put on safety glasses. Try a jump start from another vehicle. Once the engine is running, read the voltage across the battery terminals at about 2000 rpm. Should read about 13.5 to 14.5 volts if charging system is working.

Do NOT disconnect the battery while the engine is running, ever.

 

battery voltage is 12,the voltage on the fuses are 11.77 but I didn’t think it could be alternator since we only drove it home & that’s it lol. Didn’t have trouble starting before hand.

 

I’ll try to jump start when I get off work. Battery was reading 12v when I put it on and didn’t crank.

 

12.0 is too low. A healthy fully charged battery should be 12.7V
Make sure all the connections are clean and tight.