Have a look at the single plug just by the front of the battery tray, this is the starter solenoid wire from the car loom down to the starter. It could also be the starter inhibitor relay (not just on automatics like the Haynes book of lies says), IIRC, it is the big relay, front left of the fusebox. Mine quit the other day, it would crank if you flashed the starter direct from the battery but not turn on the key.