GMC SIERRA 2020 Owner's Manual page 316

Connections OK
If all of the trailer connections are
detected (Running Lights, Left Turn
Signal Light, Right Turn Signal
Light, Reverse Lights, and Electric
Brakes, if equipped), the view will
display OK.
Connection Problem
If any of the trailer connections are
not detected, a message about the
connection issue will appear on the
Driver Information Center (DIC). The
infotainment display will also show
the connection issue in the
Connection Status view.
Diagnose View
Touch Diagnose to see more
information about the connection
problem.
This view will display the names of
the trailer connector pins, a graphic
of the trailer connector, and a
graphic of the back of the trailer.
Any connector pin that failed will be
amber color, and the location of the
corresponding connection will be
highlighted on the graphic of the
back of the trailer.
The Running Lights connection may
not detect partial outages. Activate
the light test to check all trailer
lamps. See Light Test following.
If the trailer is not equipped with
reverse lights or electric brakes and
you are receiving failure messages
in the DIC or on this view, turn off
the Reverse Lights Alert or the
Electric Brakes Alert setting in the
trailer s profile page.
Light Test
Touch Start Light Test to cycle the
trailer lights 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.
Driving and Operating
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.
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