Just go a new 560 and had a drain too. I found the antenna was not shutting off. It didn't keep running, just stopped and the motor would stay warm. I could hear a small click when the battery was connected / disconnected. I haven't fix it yet, I just unplugged it at the antenna and no more drain. If this is it, you could feel the motor after the car is shut off for a while and with a good battery, it will feel warm. Dash switch didn't make any difference.