2012 GMC Canyon Owner's Manual - Page 141

Lighting Dome Lamp Override The dome lamp override button is located below the exterior lamps control. 6-7 Lighting Features Exit Lighting The interior lamps will come on when the key is removed from the ignition. The lamps will not come on if the dome override button is pressed in. E (Dome Lamp Override): Press this button in to make the dome lamps remain off when the doors are open. To return the lamps to automatic operation, press E again and return it to the out position. Battery Load 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 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 of the power needed for very high electrical loads.