GMC Cadillac CTS 2004 Owner's Manual page 292

Turn Signals When Towing a Trailer
When you tow a trailer, your vehicle may need a
different turn signal flasher and/or extra wiring. Check
with your dealer. 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.
On a long uphill grade, shift down and reduce
your speed to around 45 mph (70 km/h) to
reduce the possibility of the engine and the
transmission overheating.
4-44
Parking on Hills
CAUTION:
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You really should not park your vehicle, with a
trailer attached, on a hill. If something goes
wrong, your rig could start to move. People
can be injured, and both your vehicle and the
trailer can be damaged.
But if you ever have to park your rig on a hill, here's
how to do it:
1. Apply your regular brakes, but don't shift into
PARK (P) for an automatic transmission or into gear
for a manual transmission.
When parking uphill, turn your wheels away from
the curb. When parking downhill, turn your wheels
into the curb.
2. Have someone place chocks behind the
trailer wheels.