what would cause the hazard flashers to come on when the car is off

Hello, The hazard light switch may be the cause, but that switch does not power the lights directly, it just tells the smart junction box to turn them on. Your car is actually very advanced, and has quite the computer network, so troubleshooting becomes difficult without professional scan tools. There is also a pretty common issue with the FCIM - a control module which controls functions of things like radio, air conditioner, lights, etc... Just be aware that this repair can run into the hundreds with ease. The biggest problem is that you will not have a great way to test it or get it tested without having the issue all the time, and it may turn on while driving as well.