2001 starting issue

Hello we have a 01 3.8 with 130k. It will sometimes not start. It does not crank it, you turn the key everything powers up and once you go all the way to start it does nothing at all! My g/f also claims the turn signals work and don't work sometimes. The security light also has its own mind. Where do I begin?

Thanks Derek

When it won't sstart does the security lite stay on?

The security light has not been on when this problem occurs.

When this happens check for 12v at the starter solenoid terminals while someone holds the key in the crank position.