99 Regal LS Ocassional Dead Battery

I have a problem with an occassional dead battery after the car sits for 8 hours. I noticed that the door lights go out imediately after closing the door usually. But sometimes it may be 25 or 30 seconds before they go out. Since the dead battery problem is extremely infrequent it is difficult to diagnose the problem. I noticed someone on another board was having a simular problem with a 2000 Le Sabre. Has anyone else experienced this problem? Does anyone know if there is a relay that controls the door lights and where the relay is located? Thanks.

The device that controls the courtesy lights and retained accessory power (RAP) is the body control module (BCM). The BCM will have the most parasitic draw of any electrical component and may explain the battery drain if it is defective. Also other components could cause the problem. On RAP, it is part of battery protection and is supposed to cut off all power to accessories after 10 minutes from time the driver exits the car or when lock is pressed on the remote.

Also, how old is the battery and has it been tested to make sure it is OK.

The device that controls the courtesy lights and retained accessory power (RAP) is the body control module (BCM). The BCM will have the most parasitic draw of any electrical component and may explain the battery drain if it is defective. Also other components could cause the problem. On RAP, it is part of battery protection and is supposed to cut off all power to accessories after 10 minutes from time the driver exits the car or when lock is pressed on the remote.

Also, how old is the battery and has it been tested to make sure it is OK.
Thanks for the info, I think you pointed me in the right direction. I searched this forum using "retained accessory power " and "battery rundown protection". I found someone with a 98 Pontiac that had a parasitic drain. The drain was an amplifer in the stock stereo system. This could be my problem. The problem has only occurred when my wife drives the car to work, never with me. She has a habit of leaving the radio on and using the automatic cut off feature, When she opens car door the radio shuts off. I almost never listen radio in the car. I am wondering if a bad or sticking door switch could be causing this problem. The battery is less than two years old and tested ok.

Thanks for the info, I think you pointed me in the right direction. I searched this forum using "retained accessory power " and "battery rundown protection". I found someone with a 98 Pontiac that had a parasitic drain. The drain was an amplifer in the stock stereo system. This could be my problem. The problem has only occurred when my wife drives the car to work, never with me. She has a habit of leaving the radio on and using the automatic cut off feature, When she opens car door the radio shuts off. I almost never listen radio in the car. I am wondering if a bad or sticking door switch could be causing this problem. The battery is less than two years old and tested ok.

Also check the easy stuff if you already haven't. Trunk light, glove box light, hood light, if equipped. Your battery should a reserve capacity of around 120. Divide by 4 and you get 30 mA (milliamps). So parasitic draw should not exceed 30mA otherwise the battery will be affected/drained.

When the door is opened and the radio shuts off that initiates the RAP 10 minute battery rundown protection. RAP relay is located behind the glovebox. But I've seen on Pontiacs and Regals where the low frequency amp doesn't shut down completely for some unexplained reason. If you have the Premium II sound system you'll have the LFA. One guy had to add a separate turn off switch. In a worst case scenario a defective ignition switch and harness assembly could cause the problem.

Also search Oldsmobile Intrigue forum for parasitic draw. One guy found his BCM module (body control) was acting up and had a parasitic draw of 270mA which is not good. Either way it will be through the process of elimination of which electrical/electronic component is causing the problem. Also a load bar is available to hookup to the battery negative for load testing. It will have test points for a multimeter in the current position.

Good luck!