2008 GMC Envoy Owner's Manual - Page 152

Entry Lighting The vehicle has entry lighting. When any door is opened, the dome lamps come on as long as the dome override lamp override button is not pressed in. When all the doors are closed, the lamps stay on for a short period of time and then turn off automatically. If you use the Remote Keyless Entry (RKE) transmitter to unlock the vehicle, the interior lamps come on for a short time whether or not the dome lamp override is on. 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 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. A high electrical load occurs when several of the following loads are on: headlamps, high beams, fog lamps, rear window defogger, climate control fan at high speed, heated seats, engine cooling fans, trailer loads, and loads plugged into accessory power outlets. Exit Lighting With exit lighting, the interior lamps come on when you remove the key from the ignition. If the dome override is off, these lamps stay on for a short period of time and then go out. Reading Lamps The reading lamps are located in the front console. Press the lens on the lamps to turn the reading lamps on or off. 3-18