I have a 2001 Deville DHS. Today I ran the battery down by playing the radio. When I went to start it, it just clickied because the battery was too low to crank. I put my battery charger on it and selected the engine start mode. After a few seconds I attempted to crank the car but It just clicked,as the battery wasn't charged enough yet. I let it sit a few minutes and the car finally started but the Dash and the Climte control displays were blank. I turned the car off and restarted and the displays lit but immediatley went blank again once that car started. I then killed the car and turned the key to the 'RUN' position without starting and the displays stay lit... but the when I start the car they go out.. I have repeated this several times without starting the car and they stay lit but once I start the car they go out. Any ideas?