Trailer Lamps - Without TRM
System Diagram
Network Message Chart
BCM Network Input Messages
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| Gear position | PCM | Indicates the transmission is in reverse gear to the BCM. When the transmission is in REVERSE and the ignition in RUN, the BCM provides voltage to the reversing lamps. |
GWM Network Input Messages
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| Turn signal switch status | SCCM | Indicates the turn signal stalk position on the LH steering column multifunction switch (left/right lane change or turn signal on or off). |
| Parklamp status | BCM | A command to activate/deactivate the park lamps output. |
| Turn indication request | BCM | A command to activate/deactivate the exterior mirror turn indicator. |
| Stop lamp brake request | BCM | A command to activate/deactivate the stop lamps output. |
Trailer Stop-Turn Lamps
The SCCM monitors the LH steering column multifunction switch position. When the LH steering column multifunction switch is in the left or right turn position, the SCCM sends a message over the HS-CAN2 to the GWM then the GWM sends the message to the BCM over the HS-CAN1 indicating a request for the LH or RH turn signal.
When the BCM receives a request for a turn signal, the BCM provides a switched ground path to the LH or RH stop/turn trailer tow relay (integral to the BJB). When the BCM provides ground the LH or RH stop/turn trailer tow relay, the relay is energized and the relay provides turn lamp voltage to the trailer tow connector.
When the BCM receives input from the stoplamp switch indicating that the brake pedal is being pressed, the BCM provides a ground path to the LH and RH stop/turn trailer tow relay (integral to the BJB). When the BCM provides ground the LH and RH stop/turn trailer tow relay, the relay is energized and the relay provides stop lamp voltage to the trailer tow connector.
Trailer Parking Lamps
The BCM monitors the headlamp switch position by sending voltage signals on multiple circuits to the headlamp switch. There is one circuit for each headlamp switch position. At any given time, one of the signal circuits is switched to ground to indicate the headlamp switch position.
When the parking lamps or headlamps position is selected, the BCM provides a ground path to the parking lamps trailer tow relay. When the BCM provides ground the parking lamps trailer tow relay, the relay is energized and the relay provides parking lamp voltage to the trailer tow connector.
Trailer Reversing Lamps
When the transmission is in REVERSE, the PCM sends a message over the HS-CAN1 to the BCM indicating the transmission is in REVERSE. The BCM provides ground to the reversing lamps trailer tow relay (integral to the BJB) when it receives the message that the transmission is in REVERSE and the ignition is in RUN. When the BCM provides ground the reversing lamps trailer tow relay, the relay is energized and the relay provides reversing lamp voltage to the trailer tow connector.