My 1993 400e will not start!

I'm pulling my hair out on this..

Last week, it refused to start. Turning the key produced one click.
I thought the battery might be weak, so I jumped it off my truck, started right up.
Drove it down the road, started back up twice, third start was no go...

Figured it was the battery so replaced that.
Still just one click..

Starter under warranty, so replaced it from Napa with brand new one , not remanufactured, new.

Put it on today.
Click only...same thing, No change..


I've had problems with the immovilizer before, when I did, it wouldn't even click.
So it's not that.


Anyone help point me in the right direction to save my hair?