car has a mind of it's own

I have just purchased a 2000 Volvo C70 HPT Convertible. I have discovered a problem that I have not been able to find a solution for and I am hoping that someone might have some insight into this issue:

The Electronic climate control and the audio system turn itself on and off independently when the car is not running and the ignition is turned off. Sometimes the climate control does not turn off when the ignition is turned off, and sometimes it will turn itself on when the car is off and in park… also the audio system will turn itself on when in park and the ignition is off.

I had a new ignition put in…. unfortunately that is not the issue. I still have the same problem. Some days the climate control and audio shuts off when the ignition is turned off and some days they turn on independently and drain the battery…

I sure would appreciate any insight that someone might have in solving this problem.

Thanks!