01 Ranger doesnt turn over

I'm working on my inlaws 01 Ford Ranger 2.3L automatic. She went to crank it the other morning and it wouldn't turn over. Like there wasn't any power going to the starter. There is no relay on the firewall, just in the power distribution box. I checked the fuses and swapped relays, electronics isn't my strong suit but I can check things with a little guidance, anyway I decided to jump the starter and it would only spin not engage. I pulled it off and had it tested, it turned out to be bad, so I put a new one on. it still would not turn over. I'm thinking maybe the safety neutral switch, but not sure. I'm also not sure about the theft system, if it even has one. This truck is a plain jane model. It does have a theft light that blinks when the key is turned on. She said it has always blinked when cranking, but goes off when the motor is started. Any help would be appreciated.