Exterior Lighting - System Operation and Component Description: DRL

System Diagram 

Courtesy of FORD MOTOR COMPANY

Courtesy of FORD MOTOR COMPANY

Network Message Chart 

BCM Network Input Messages 

DRL 

For the halogen headlamp system, the DRL system utilizes the existing circuitry and components from the headlamp low beam system. The DRL system operates the low beam headlamps at a reduced intensity.

For the High Intensity Discharge (HID) headlamp system, DRL system utilizes a halogen bulb in the headlamp assembly.

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 configurable 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 a turn signal is active, the corresponding daytime running lamp will turn off. Once the turn signal is deactivated, the daytime running lamp returns to normal operation.

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.

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 - System Operation and Component Description .

Autolamps 

System Diagram 

Courtesy of FORD MOTOR COMPANY

Courtesy of FORD MOTOR COMPANY

Network Message Chart 

BCM Network Input Messages