1996 buick park ave radio comes on when car is off

Sounds like you need an exorcism.

Have had a similar issue on my 96 Buick park ave. My antenna was/is stuck in the up position and even though the car was not running, it would make a continual clicking like it was trying to turn off. Long story short, I took it to a car audio place and they disconnected the wire to the antenna in the trunk. No more clicking or draining the battery and the radio works just fine. Only thing is is that the antenna is stuck up and you can't take it through an automatic car wash. I could have chosen to replace the antenna but since the clicking has stopped and the radio works, I don't care.