GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - CRC - 2/18/20
Driving and Operating
297
Warning (Continued)
.
If the trailer brakes are not operating
properly at any time, or if a DIC
message indicates problems with the
trailer connections or trailer brakes,
carefully pull the vehicle over to the
side of the road when traffic
conditions allow.
Trailer Tires
Special Trailer (ST) tires differ from vehicle
tires. Trailer tires are designed with stiff
sidewalls to help prevent sway and to
support heavy loads. These features can
make it difficult to determine if the trailer
tire pressures are low only based on a visual
inspection.
Always check all trailer tire pressures before
each trip when the tires are cool. Low trailer
tire pressure is a leading cause of trailer tire
blow-outs.
If the vehicle is equipped with a trailer tire
pressure monitoring system, see the trailer
tire pressure monitoring system description
and the trailering app.
Trailer tires deteriorate over time. The trailer
tire sidewall will show the week and year
the tire was manufactured. Many trailer tire
manufacturers recommend replacing tires
more than six years old.
Overloading is another leading cause of
trailer tire blow-outs. Never load your trailer
with more weight than the tires are
designed to support. The load rating is
located on the trailer tire sidewall.
Always know the maximum speed rating for
the trailer tires before driving. This may be
significantly lower than the vehicle tire
speed rating. The speed rating may be on
the trailer tire sidewall. If the speed rating is
not shown, the default trailer tire speed
rating is 105 km/h (65 mph).
Trailering App
Trailer Lights App
If equipped, the Trailer Lights App is on the
Home Page of the infotainment display.
Touch Start to cycle the trailer lamps on and
off to determine if they are working. The
test follows this sequence:
1. The running lights turn on first and
remain on throughout the sequence.
2. The brake lights turn on for about
two seconds.
3. The left turn signal light flashes three
times.
4. The right turn signal light flashes three
times.
5. The reverse lights turn on for about
two seconds.
6. Steps 2
–
5 repeat for approximately
one minute and 45 seconds, or until the
test deactivates.
Touch Stop to stop the test. The test will
automatically end after one minute and
45 seconds.
The sequence also deactivates when any of
the following occur:
.
The ignition is turned off.
.
The transmission is shifted out of P (Park).
.
The brake pedal is pressed.
.
The turn signal is activated.
.
The hazard warning lights are activated.
Trailering App
If equipped, the Trailering App is on the
Home Page of the infotainment display.