alternator GMC ENVOY 2009 Owner's Manual

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.
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 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 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 are on, such as: 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.
EPM works to prevent excessive discharge of the
battery. It does this by balancing the generator’s output
and the vehicle’s electrical needs. It can increase
engine idle speed to generate more power, whenever
needed. It can temporarily reduce the power demands of
some accessories.
Normally, these actions occur in steps or levels, without
being noticeable. In rare cases at the highest levels
of corrective action, this action may be noticeable to
the driver. If so, a Driver Information Center (DIC)
message might be displayed, such as BATTERY
SAVER ACTIVE, BATTERY VOLTAGE LOW, or
LOW BATTERY. If this message is displayed, it is
recommended that the driver reduce the electrical loads
as much as possible. SeeDIC Warnings and Messages
on page 3-51.
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