GMC 2012 Sierra Denali Owner's Manual page 335

Other ITBC-Related DIC Messages
In addition to displaying TRAILER
GAIN and TRAILER OUTPUT
through the DIC, trailer connection
and ITBC system status are
displayed on the DIC.
TRAILER CONNECTED: This
message will be briefly displayed
when a trailer with electric brakes is
first connected to the vehicle. This
message will automatically turn off
in about 10 seconds. The driver can
also acknowledge this message
before it automatically turns off.
CHECK TRAILER WIRING: This
message will be displayed if:
1. The ITBC system first
determines connection to a
trailer with electric brakes and
then the trailer harness becomes
disconnected from the vehicle.
If the disconnect occurs while
the vehicle is stationary, this
message will automatically turn
off in about 30 seconds. This
message will also turn off if the
driver acknowledges this
message or if the trailer harness
is re-connected.
If the disconnect occurs while
the vehicle is moving, this
message will continue until the
ignition is turned off. This
message will also turn off if the
driver acknowledges this
message or if the trailer harness
is re-connected.
2. There is an electrical fault in the
wiring to the electric trailer
brakes. This message will
continue as long as there is an
electrical fault in the trailer
wiring. This message will
also turn off if the driver
acknowledges this message .
Driving and Operating
To determine if the electrical fault is
on the vehicle side or trailer side of
the trailer wiring harness
connection, do the following:
1. Disconnect the trailer wiring
harness from the vehicle.
2. Turn the ignition to LOCK/OFF.
3. Wait 10 seconds, then turn the
ignition back to ON/RUN.
4. If the CHECK TRAILER WIRING
message re-appears, the
electrical fault is on the
vehicle side.
If the CHECK TRAILER WIRING
message only re-appears when
connecting the trailer wiring
harness to the vehicle, the
electrical fault is on the
trailer side.
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