I have a 2006 Cadillac CTS with around 130,000 miles. A problem I’m having with it is that is sometimes won’t start when I turn the key. All the dash lights come on as well as the radio, but there is no crank. After about 5-6 times turning the key it will finally turn over. This happens about 1-2 times per week. I want to rule out the battery and Alternator as they were both replaced about a month ago. What could be going wrong?
I would check the positive cable going from the battery to the starter. Make sure that both ends haven't broken down, and are connected securely.
After that, I would suspect the starter, specifically the solenoid. This is a common issue with old Toyotas (whose solenoid itself was rebuildable, saving $$$).
GM had some ignition switch issues. Make sure your recalls have been fixed.