Exterior Lighting - System Operation and Component Description: DRL
System Diagram
Network Message Chart
BCM Network Input Messages
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| Gear position | PCM | Indicates the GSM request to the BCM. When the GSM has selected any position other than park, the BCM activates the DRL. |
DRL
The DRL system utilizes the existing circuitry (halogen headlamps) and components from the headlamp low beam system.
The DRL system operates the low beam headlamps at a reduced intensity.
The BCM monitors the ignition status, the headlamp switch and autolamp status.
There are two types of DRL. Conventional (where it is required) and configurable.
When equipped with conventional DRL, the DRL are active in any headlamp switch position except the HEADLAMPS position.
When equipped with configuable DRL, the DRL may be enabled through the IPC message center. When enabled, the DRL are active only in the AUTOLAMPS headlamp position. When autolamps request the headlamps on, the DRL are de-activated.
The DRL are activated when the following conditions are met:
- the ignition is in run
- the headlamps have not been turned on by the autolamp system or the headlamp switch
- the transmission is not in park
When the transmission is in not in PARK, the PCM sends a message over the HS-CAN1 to the BCM indicating the transmission is not in PARK.
Vehicles with LED headlamps utilize a ballast, mounted to each headlamp assembly, that controls the voltage to the high beam, low beam, parking and turn Light Emitting Diodes (LEDs) within the headlamp assembly and the low beam DRL function.
The BCM also provides Field Effect Transistor (FET) protection of the exterior lamps switched voltage and DRL output circuits. When an excessive current draw is detected, the BCM disables the affected circuit driver.
Refer to: Module Controlled Functions - Overview .