Have a Car Question? Ask a Mechanic Online.
Can you provide some more detail on the problem you are having? I cant quite picture the failure... Does the key turn normally in the switch, and does the movement feel normal (no binding, sticking, etc)? If it does turn normally, but doesnt work, how do you get the car started after you pull the battery cable? What part of the switch did you replace, the part the key goes in, or the electrical part? Any information you can provide will help to diagnose the failure here...
Htis one is a pretty tough problem to diagnose remotely like this; the engine control system and vehicle wiring on tehis model are complex.
If you installed a brand new ignition switch (the electrical part of the assembly) then it is probably safe to rule out the ignition switch as a cause here.
Other than that, the first thing that comes to mind is a stucl relay, allowing the ignition system, fuel pump, and control module to remain powered up after the accessory feed circuit from the ignition switch loses power. There are several likely candidates for this on the wiring schematics for this model. Try pulling relays one at a time in the underhood panel, to see which ones kill the engine when it is running.
The no crank problem may be a separate issue; the primary side of the starter relay is powered up by the
transmission range switch which in turn is powered by a 5 amp fuse in the power distribution box.
Perhaps removing and inspecting the wiring behind the fuse/ relay panels for burned or shorted wires might yield a clue.