Hummer 2007 H3 - Manual (Page 105)

Engine Coolant Heater
Your vehicle may have this feature.
In very cold weather, 0°F (–18°C) or colder, the
engine coolant heater can help. You will get easier
starting and better fuel economy during engine
warm-up. Usually, the coolant heater should be
plugged in a minimum of four hours prior to starting
your vehicle. At temperatures above 32°F (0°C),
use of the coolant heater is not required. Your
vehicle may also have an internal thermostat in the
plug end of the cord. This will prevent operation of
the engine coolant heater when the temperature is
at or above 0F (
−
18C) as noted on the cord.
To Use the Engine Coolant Heater
1. Turn off the engine.
2. Open the hood and unwrap the electrical cord.
The cord is located in the engine compartment
behind the underhood fuse block on the
driver’s side of the vehicle.
3. Plug it into a normal, grounded 110-volt
AC outlet.
{ CAUTION:
Plugging the cord into an ungrounded
outlet could cause an electrical shock.
Also, the wrong kind of extension cord
could overheat and cause a fire. You could
be seriously injured. Plug the cord into a
properly grounded three-prong 110-volt AC
outlet. If the cord will not reach, use a
heavy-duty three-prong extension cord
rated for at least 15 amps.
4. Before starting the engine, be sure to unplug
and store the cord as it was before to keep it
away from moving engine parts. If you do not, it
could be damaged.
How long should you keep the coolant heater
plugged in? The answer depends on the outside
temperature, the kind of oil you have, and some
other things. Instead of trying to list everything here,
we ask that you contact your dealer in the area
where you will be parking your vehicle. The dealer
can give you the best advice for that particular area.
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