Trailering Systems 2-59
Description and Operation
Trailering Description and Operation
Trailering System Overview
Begin the trailering system diagnosis with Diagnostic
System Check - Trailering. The Diagnostic System
Check - Trailering will provide a complete strategy to
locate and repair a vehicle trailering electrical fault. Not
following this strategy may cause additional diagnostic
time and/or misdiagnos is.
The trailering system consists of the following:
• Trailer Lighting, refer to Trailer Lamps Malfunction
for additional diagnostic information.
• Trailer Brakes, refer to Trailer Brake Malfunction
for additional diagnostic information.
• Trailer Battery Charging System, refer to Trailer
Battery Charging Malfunction for additional
diagnostic information.
• Trailer Detection, refer to Trailer Detection
Malfunction for additional diagnostic information.
• Trailer Tire Pressure Monitoring System, refer to
Trailer Tire Pressure Monitoring Malfunction for
additional diagnostic information.
• Trailer Theft Detection.
When a trailer is detected on a vehicle equipped with
side blind zone detection, rear park assist, and/or rear
cross traffic alert, the vehicle will automatically turn
these features off. These features are turned off to
prevent false detections due to the trailer obstructing
the view of the sensors.
7–Terminal Tow Vehicle Electrical Receptacle Pinout
(North America)
• Terminal A – Trailer Backup Lamp Control
• Terminal B – Ground
• Terminal C – Trailer Brake Control
• Terminal D – Right Trailer Stop/Turn Signal Lamp
Control
• Terminal E – B+
• Terminal F – Trailer Park Lamp Control
• Terminal G – Left Trailer Stop/Turn Signal Lamp
Control
13–Terminal Tow Vehicle Electrical Receptacle
Pinout (Export)
• Terminal 1 – Left Trailer Turn Signal Lamp Control
• Terminal 2 – Trailer Fog Lamp Control
• Terminal 3 – Ground
• Terminal 4 – Right Trailer Turn Signal Lamp
Control
• Terminal 5 – Right Trailer Park Lamps Control
• Terminal 6 – Trailer Stop Lamps Control
• Terminal 7 – Left Trailer Park Lamps Control
• Terminal 8 – Trailer Backup Lamp Control
• Terminal 9 – B+
• Terminal 10 – Ignition Voltage
• Terminal 11 – Ground
• Terminal 12 – Trailer Connecte d Signal
• Terminal 13 – Ground
Connecting Aftermarket Accessories
• Some aftermarket accessories that connect to the
X88 Tow Vehicle Electrical Receptacle will be
recognized by the vehicle as a trailer connected,
even if the accessory is not a trailer. As a result,
side blind zone detection, rear park assist, and/or
rear cross traffic alert will be turned off anytime the
vehicle detects a trailer/accessory is connected.
• Vehicles equipped with U1D/UET have trailer theft
detection that constantly monitors trailer
connected status when enabled. This is done by
randomly pulsing the lighting circuits of the trailer
when the vehicle is parked. As a result, some
aftermarket accessories may be turned ON/OFF
when connected to the vehicle with theft detection
enabled.
• Vehicles equipped with U1D/UET use pulse width
modulation voltage (PWM) for trailer lighting
functions. Some aftermarket accessories are
incompatible with PWM and may not function
correctly when connected to the trailer lighting
circuits of the vehicle.
Trailer Battery Charging System
Trailer battery charging is accomplished through
constant battery voltage from the X50A Engine Wiring
Harness Junction Block to the X88 Tow Vehicle
Electrical Receptacle. Battery voltage is supplied to
terminal E at the X88 Tow Vehicle Electrical Receptacle
at all times. If equipped, the trailer battery will
constantly be charged by the vehicle’s electrical system
anytime the trailer is connected. Some trailers require
the B+ circuit to the X88 Tow Vehicle Electrica l
Receptacle for the trailer brakes to function.
Trailer Lighting and Detection With
U1D/UET
Note:
• Some trailers utilize a trailer mounted control
module to operate some or all of the trailer lights.
These trailers may use the B+ circuit from the
trailer connector to power the trailer lighting
circuits. These trailers may not always be
detected by the Trailer Lighting Control Module
and may set faults.
• Vehicles equipped with IOR/1FL do not come
equipped with the trailering APP however may still
be equipped with a K68 trailer Lamp Control
Module.
North America (7-Terminal connector)
North American vehicles use a 7-way trailer connector
for trailering features. The K68 Trailer Lamp Control
Module is responsible for controlling the trailer lighting
on vehicles with U1D/UET. The combined trailer stop/
turn signal lamps of the trailer must draw at least 55mA
of total current to be detected as a trailer or the Trailer
Lamp Control Module will not control the lighting
circuits. The Trailer Lamp Control Module receives
serial data messages from the K9 Body Control Module
(BCM) indicating what lamps have been activated on
the vehicle. The Trailer Lamp Control Module respond s
by applying pulse width modulated voltage (PWM) to
the appropriate control circuits for the requested lamps
2022 - Silverado 1500 (New) Electrical Body Builder Manual
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