Turn Signals When Towing A Trailer; Driving On Grades - GMC 2000 Envoy Owner's Manual

Turn Signals When Towing a Trailer

When you tow a trailer, your vehicle has to have extra
-
wiring and a heavy duty turn signal flasher.
The arrows on your instrument panel will flash
whenever you signal a turn or lane change. Properly
hooked up, the trailer lamps will also flash, telling other
drivers you're about to turn, change lanes or stop.
When towing a trailer, the arrows on your instrument
panel will flash for turns even if the bulbs on the trailer
are burned out. Thus, you may think drivers behind you
are seeing your signal when they are not. It's important
to check occasionally to be sure the trailer bulbs are
still working.

Driving On Grades

Reduce speed and shift to a lower gear before you start
down a long or steep downgrade. If you don't shift
down, you might have to use your brakes so much
that they would get hot and no longer work well.
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You should use THIRD (3) when towing a trailer.
Operating your vehicle in THIRD (3) when towing a
trailer will minimize heat buildup and extend the life of
your transmission. See "Tow/Haul Mode" in the Index.
When towing at high altitude on steep uphill grades,
consider the following: Engine coolant will boil at a
lower temperature than at normal altitudes. If you turn
your engine off immediately after towing at high altitude
on steep uphill grades, your vehicle may show signs
similar to engine overheating. To avoid this, let the
engine run while parked (preferably on level ground)
with the automatic transmission in PARK (P) for a few
minutes before turning the engine off. If you do get the
overheat warning, see "Engine Overheating" in
the Index.