Went to start my 1997 Suburban Saturday morning (about 25F) and there was nothing, no interior lights, dash lights, etc. Later I went to hook up the charger thinking I'd left lights on. Opened the hood and the under hood light was also off. Hooked up the charger (was not turn on at the time) and the under hood light came on. Never turned the charger on and the she started right up. This morning (about the same temp) my wife went to start and nothing again, not home to look at it.
