2007 Cadillac STS Owner's Manual - Page 221

Reading Lamps The reading lamps are located on the overhead console. These lamps come on automatically when any door is opened. For manual operation, press the button next to each lamp to turn it on or off. If the reading lamps are left on, they automatically shut off 10 minutes after the ignition has been turned off. If the battery continues to discharge, even with the engine idling at a higher rpm setting, some electrical loads will automatically be reduced. When this occurs, the rear window defogger may take slightly longer to clear the glass and the fan may cut back to a lower speed. For more battery saving information, see "Battery Saver Active Message" under DIC Warnings and Messages on page 264. Electric Power Management The vehicle has Electric Power Management (EPM) that estimates the battery's temperature and state of charge. It then adjusts the voltage for best performance and extended life of the battery. When the battery's state of charge is low, the voltage is raised slightly to quickly put the charge back in. When the state of charge is high, the voltage is lowered slightly to prevent overcharging. If the vehicle has a voltmeter gage or voltage display on the Driver Information Center (DIC), you may see the voltage move up or down. This is normal. If there is a problem, an alert will be displayed. Battery Load Management The battery load management feature is designed to monitor the vehicle's electrical load and determine when the battery is in a heavy discharge condition. During times of high electrical loading, the engine may idle at a higher revolutions per minute (rpm) setting than normal to make sure the battery charges. High electrical loads may occur when several of the following are on: headlamps, high beams, fog lamps, rear window defogger, the climate control fan at high speeds, heated seats and engine cooling fans. 221