1987 Fiero GT automatic trans. Won't turn over-ran fine the day before. Even with a jump nothing works, radio, lights, break lights. There is no click or anything when the ignition is turned even the indash gages dont come on.

So no power anywhere? Nothing at all? I'm assuming the battery is fine since it ran the day before.

This actually happened to me one time in my fiero

What is happening is no power is getting to the car at all, no power is reaching the engine, lights, interior, etc.

This simply or not so simply means there is a severed connection from the battery.

1) Check BOTH positive and negative connections, make sure the posts are clean and make a solid metal-to-metal contact and see if there is power yet.

2) Check the power junction area (or whatever it's called) in the engine bay (on the passenger side wall near the battery). There are red wires
and such which supplies the car with power in this junction area attached to posts and inside of black plastic connectors. Look for worn or severed wires which may have come loose over the years.

When this happened to my fiero, one of the wires corroded and came loose from the post where it was bolted on and attached to other wires.

Just reconnect the loose wire(s), you may have to crimp new ends or whatever, but that should fix it.

If not, start hunting for where the 12v supply from the battery is cut off. Use a multimeter and good luck!