Totally lost all power to hvac system. Battery light is on the dash. When you try to turn on the fan switch all the 4x4 lights go off then come back on when you shut the fan switch off. Could it be a major short some where?
It sounds like you are talking about a vehicle of some sort. You should take it to your mechanic who knows about those things. I have never heard anybody speak of "hvac" in a vehicle.
What you describe sounds like a corroded connection, and you just need somebody who knows the equipment to find it.