What would make all the dash lights come on all at once and gage needles go crazy then go off?

I have the same problem but it only happens when I turn on the heater motor

I have had a 98 sunfire since new and always had this problem when the battery was low on juice or mainly when the little wire that grounds to the battery holder plate, the little wire that comes off the big negetive battery cable, this conection would get all corroded and thats when the dash lights go crazy speedometer going up and down like its possesed, clean up that connection, use petrolium jelly when you connect it back up.