What would make a '99 Chevy Suburban go click click click act like it has a dead battery when the key is in the ignition but NOT engaged and when the key is out of he ingiion it still does the click?

Answer 1

That clicking sound could be the sign of a weak, if not a totally discharged battery. Or, it could indicate a defective solenoid in the starter, or a defective bendix spring in the starter. If you are convinced that the battery is not the cause, I'd focus on the starter.