0x59 Rain/Driving-Light Status

RLS 0xe8 → LCM 0xd0.

Reports the ambient-light state and the automatic low-beam request to the Light Control Module.

When the light switch is in automatic mode, the LCM uses this message to switch the parking and low-beam lights as required.

Examples

E8 05 D0 59 10 00 74
E8 05 D0 59 30 00 54
E8 05 D0 59 31 02 57
E8 05 D0 59 32 02 54
E8 05 D0 59 50 00 34
E8 05 D0 59 51 08 3D
E8 05 D0 59 11 01 74

30 00 and 50 00 request the lights off. 31 02 uses the same light level as 30 00, but sets the light request and reports darkness.

Properties

Fixed length. Two-byte bitfield.

# Byte 1

BRIGHTNESS_LEVEL = 0b0111_0000
SENSOR_FAULT     = 0b0000_0010
LIGHT_STATE      = 0b0000_0001

# Byte 2

REASON          = 0b0001_1111

Brightness Level 0b0111_0000

DARKEST    = 0x10
DARK       = 0x20
MEDIUM     = 0x30
BRIGHT     = 0x40
BRIGHTEST  = 0x50

The physical thresholds are coding/calibration dependent.

Light State 0b0000_0001

LIGHTS_ON  = 0x01
LIGHTS_OFF = 0x00

Bit 0 is the automatic-light request. Set requests the parking and low-beam lights, clear requests them off.

Sensor Fault 0b0000_0010

Bit 1 is the RLS sensor-fault/failsafe state. A clear bit corresponds to the normal Sensor_OK state seen in RLS traffic. LCM treats this bit like an active light request, matching the RLS fail-safe behavior in which a sensor failure causes the driving lights to be switched on.

Reason 0b0001_1111

TWILIGHT    = 0x01
DARKNESS    = 0x02
RAIN        = 0x04
TUNNEL      = 0x08
GARAGE      = 0x10

LCM accepts this second byte but does not use it in its automatic-light decision path.