1994 Cadillac STS

What does it do? Does it crank and not start, or not even crank? Is there indication of power, dash lights up and such? If it does not crank, are there any messages across the info center like starting disabled due to theft? If not, and there is indication of power through the IPC, I would check for a signal to the starter. There should be a wire clipped to the front of the rear bank cam cover, that large purple wire is the start signal wire. Disconnect the two pin connector, check for power on he harness side when in crank, and if it has a signal, then the starter is most likely at fault.