I thought the Cross Fire has no backup battery too even my neighbor told me that is likely the problem to the battery drain - temperature and time lights stay lit on the instrument cluster.
I disconnected the battery and noticed the temperature and time lights blink every 15 seconds with the main battery disconnected.
I did a little more research and realized I cannot disconnect the main battery with a dying backup battery. If the SKREEM got no juice from either battery, you will end up with a lot more problems than battery drain.
I believe the Cross Fire is a 2003 SLK 320 with a better looking skin from Chrysler.