The factory security system will not disable the starter-just fuel.Check for power on the purple wire at the starter-if you do check the power and grounds,if they test ok its a starter.If there is no power check the ign A 40 amp fuse for power when turning the key to crank.If not check the ignition switch and wireing
Check power power with the key to crank on the 10 amp crank fuse-if thats ok check for power into the n/s switch yellow wire and power out on the purple wire.
At the starter relay-pin 85 should be power and 86 ground-
Start at the relay-there is a schematic on the relay pins 86 and 30 jumperd should make the starter crank. -the other 2 wires are a switched power and ground .There is a mian ground by the distributor that like to brake.