Turn Signal and Hazard Lamps
System Diagram
| Item | Description |
|---|---|
| 1 | HS-CAN2 |
| 2 | SCCM |
| 3 | GWM |
| 4 | HS-CAN1 |
| 5 | Start/Stop switch |
| 6 | Hazard switch |
| 7 | BCM |
| 8 | LH exterior mirror |
| 9 | RH exterior mirror |
| 10 | DDM |
| 11 | PDM |
| 12 | LH steering column multifunction switch |
| 13 | MS-CAN |
| 14 | RH rear turn lamp |
| 15 | LH rear turn lamp |
| 16 | RH front turn lamp |
| 17 | LH front turn lamp |
| 18 | RH headlamp |
| 19 | LH headlamp |
Network Message Chart
BCM Network Input Messages
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| Turn signal switch status | GWM | Indicates the turn signal stalk position on the LH steering column multifunction switch (left/right lane change or turn signal on or off). The BCM activates the left/right turn signals based on this input. |
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). |
| Turn indication request | BCM | A command to activate/deactivate the exterior mirror turn indicator. |
DDM and PDM Network Input Messages
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| Turn indication request | GWM | A command to the DDM or PDM to activate/deactivate the exterior mirror turn indicator. |
Turn Signals
The SCCM monitors the LH steering column multifunction switch position. When the LH steering column multifunction switch is in the LH TURN or RH 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 supplies on/off voltage to the appropriate rear turn lamps. The LH and RH rear turn lamps share the same circuits as the LH and RH stoplamps.
The BCM sends a turn indicator command message over the HS-CAN1 to the GWM then the MS-CAN to the door modules for the exterior mirror turn lamps.
The timed on/off cycle for turn lamps is determined by the BCM and is set to flash approximately 70 times per minute if both the front and rear turn signal lamps operate correctly.
If a front or rear turn signal lamp is inoperative, the BCM fast flashes the remaining turn lamp(s) approximately 150 times per minute to indicate a LED outage to the driver.
The turn lamps are Light Emitting Diodes (LEDs) and have an outage circuit that tells the BCM when the Light Emitting Diodes (LEDs) are inoperative. During normal operation, when voltage is applied to the turn Light Emitting Diodes (LEDs), the feedback circuit sends the same voltage back to the BCM through the outage circuit. If the Light Emitting Diodes (LEDs) are inoperative the BCM will not receive this voltage feedback through the outage circuit.
The LH steering column multifunction switch has 2 detents for the left turn position and 2 detents for the right turn position. When placed in the first detent and released, the corresponding turn signals flash 3 times and turn off. When the LH steering column multifunction switch is moved to the second detent, the turn signal flashes until the steering wheel is turned in the opposite direction.
The BCM also provides Field Effect Transistor (FET) protection of the turn lamp output circuits. When an excessive current draw is detected, the BCM disables the affected turn lamp circuit driver. Refer to: Module Controlled Functions - System Operation and Component Description .
Hazard Lamps
The BCM sends a voltage signal to the hazard flasher lamp switch to monitor for a hazard lamp function request. When the hazard flasher lamp switch is pressed, the voltage signal is routed to ground, indicating a request to activate or deactivate the hazard lamp function.
When the BCM receives a request for the hazard lamps, the BCM supplies on/off voltage to all the turn lamps.
The timed on/off cycle for the hazard lamps is approximately 70 times per minute, regardless of LED outage.