2011 GMC Savana 1500 Passenger Owner's Manual - Page 168

6-6 Lighting E DOME OFF: Press this button in and the dome lamps remain off when a door is opened. Press the button again to return it to the extended position so that the dome lamps come on when a door is opened. Reading Lamps For vehicles with reading lamps, press the button located next to each lamp to turn it on or off. The vehicle may also have reading lamps in other locations. The lamps cannot be adjusted. Lighting Features Entry/Exit Lighting The vehicle has an illuminated entry/exit feature. The dome lamps come on if the E button is in the out position, when a door is opened or the key is removed from the ignition. Battery Load Management The vehicle may have 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 bring the charge back up. When the state of charge is high, the voltage is lowered slightly to prevent overcharging. If the vehicle has a voltmeter gauge or a 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. The battery can be discharged at idle if the electrical loads are very high. This is true for all vehicles. This is because the generator (alternator) may not be spinning fast enough at idle to produce all the power that is needed for very high electrical loads.