Mazda CX-9 2007 Service Highlights page 477

Illumination operation
1. When the light switch is in the AUTO position the illumination sensors in the auto light sensor (installed in the
windshield) detect the illumination level above and in front of the vehicle.
2. If the upward or forward illumination sensors detect approx. 2000 lux or less in front of and above the vehicle,
the headlight and TNS illumination control signal is sent to the auto light/wiper control module.
3. The microcomputer in the auto light/wiper control module receives the control signal and sends current (1) to
transistor A, causing the transistor A to turn on.
4. When transistor A turns on, the TNS relay also turn on. At the same time, the TNS illuminate.
5. The microcomputer in the auto light/wiper control module receives the control signal and sends current (2) to
transistor B, causing the transistor B to turn on.
6. When transistor B turns on, the headlight relay (LO) also turns on. At the same time, the headlights (low-beam)
illuminate.
B+
TNS H/L LOW
RELAY RELAY
TAIL
TNS
2G
(1)
TRANSISTOR A
2M 2N 2L
HEAD AUTO
TNS
OFF
LIGHTING SYSTEMS
B+
H/L HI
RELAY
HIGH-BEAM
ILLUMI
INDICATOR
LIGHT
HEAD LIGHT
(LOW-BEAM)
2K
(2)
TRANSISTOR B
2O
AUTO
LIGHT
PASS
HI SENSOR
LO
LIGHT SWITCH
B+
B+
ROOM
BCM
HEAD LIGHT
(HIGH-BEAM)
2D
2E 2H 2A 2C
IG1
METER
INSTRUMENT
CLUSTER
AUTO LIGHT/WIPER
CONTROL MODULE
2F
DLC-2
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