My 2011 Sonata is dead. While there is 12V in the fuse panel none of the lights come on and there is no response when pushing the start button.
The car worked just fine yesterday. This morning when my daughter tried to go to church, the car was completely dead. It first looked like the battery was dead because no lights would come on and the control panel was dead. I checked the battery and it was fully charged. I took voltage readings on the engine compartment fuse panel and there is 12V on all of the fuses.
How did you check the battery
If you use digital multimeter across battery posts, everything off, the generic spec for a full charge is 12.6 volts. Under 12.4 volts, you need to charge it, just my opinion. Did try a jump box or battery cables? I've seen old batteries set in the back yard all winter that would show 12 volts, but, it won't start a vehicle. good luck
Also check and clean the battery terminal connections.
I tested the battery with a digital multimeter. It was 12.6V. I checked the voltage on the positive side of several fuses in the engine compartment fuse box and still got 12.6V. I attached a battery charger with a 75 Amp start function and still dead. None of the interior lights will come on. It's as if the battery was pulled out completely. There must be some master component that has failed and is preventing everything else from working.
With leads touching battery posts, have helper turn key to crank, how does the reading react? Does the reading stay the same, no drop? If it drops, how far does it drop? Pick any electrical component, hopefully one that has a diagram that is easy for us to trace. I can then hopefully post a wiring diagram, we can check voltage and ground from stem to stern on component. The diagram is starter circuit w/o smart key. When battery voltage is lost, some modules may to be reprogrammed or relearn. Sometimes the security system can be affected.
