2001 Z7 Electrical Issue

[kjctaco]

I went to start my 2001 chevrolet z71 today and when i cranked it it turned over, ran for 2 seconds and then shut off. I cranked it again and nothing, did not attempt to turn over and I noticed all the interior lights shut off and there were no instrument display lights. Tried several more times and nothing. It was completely dead as if there was no battery. I waited a few minutes, disconnected and thenreconnected the battery to try to reset it and it fired right up. It did this about 6 months ago, same symptoms. Truck is a 5.3l, has 100,000 miles and a new battery and alternator within the last year. What would cause this?

Thanks for any help

[kjctaco]

Any ideas?