Engine Heater - GMC 2015 Sierra Denali Owner's Manual

9-28 Driving and Operating

Engine Heater

The engine heater can provide
easier starting and better fuel
economy during engine warm-up in
cold weather conditions at or below
18°C (0°F). Vehicles with an
engine heater should be plugged in
at least four hours before starting.
An internal thermostat in the
plug-end of the cord may exist,
which will prevent engine coolant
heater operation at temperatures
above 18°C (0°F).
If the vehicle has a diesel engine,
see the Duramax diesel
supplement.
To Use the Engine Coolant
Heater
1. Turn off the engine.
2. Open the hood and unwrap the
electrical cord. The cord is
secured to the driver side fender
with a clip, next to the engine
compartment fuse block.
Carefully remove the wire tie
that bundles the electrical plug.
Do not cut the electrical cord.
Check the heater cord for
damage. If it is damaged, do not
use it. See your dealer for a
replacement. Inspect the cord for
damage yearly.
3. Plug the cord into a normal,
grounded 110-volt AC outlet.
Warning
Improper use of the heater cord
or an extension cord can damage
the cord and may result in
overheating and fire.
Plug the cord into a
three-prong electrical utility
receptacle that is protected
Warning (Continued)
by a ground fault detection
function. An ungrounded
outlet could cause an electric
shock.
Use a weatherproof,
heavy-duty, 15 amp-rated
extension cord if needed.
Failure to use the
recommended extension cord
in good operating condition,
or using a damaged heater or
extension cord, could make it
overheat and cause a fire,
property damage, electric
shock, and injury.
Do not operate the vehicle
with the heater cord
permanently attached to the
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