ATC-100
TROUBLE DIAGNOSIS
Sunload Sensor Circuit
EJS0037I
COMPONENT DESCRIPTION
The sunload sensor is located on the instrument mask. It detects
sunload entering through windshield by means of a photo diode. The
sensor converts the sunload into a current value which is then input
into the auto amplifier.
SUNLOAD INPUT PROCESS
The auto amp. also includes a processing circuit which averages the variations in detected sunload over a
period of time. This prevents drastic swings in the A/C system operation due to small or quick variations in
detected sunload.
For example, consider driving along a road bordered by an occasional group of large trees. The sunload
detected by the sunload sensor will vary whenever the trees obstruct the sunlight. The processing circuit aver-
ages the detected sunload over a period of time, so that the (insignificant) effect of the trees momentarily
obstructing the sunlight does not cause any change in the A/C system operation. On the other hand, shortly
after entering a long tunnel, the system will recognize the change in sunload, and the system will react accord-
ingly.
DIAGNOSTIC PROCEDURE FOR SUNLOAD SENSOR
SYMPTOM: Sunload sensor circuit is open or shorted. (25 or
−
25) is
indicated on auto amp. as a result of conducting Self-diagnosis
STEP 2.)
1.
CHECK SUNLOAD SENSOR CIRCUIT BETWEEN SUNLOAD SENSOR AND GROUND
Disconnect sunload sensor harness connector.
OK or NG
OK
>> GO TO 2.
NG
>> GO TO 4.
RJIA2330E
RJIA0814E
Terminal
Voltage
(+)
(-)
Sunload sensor
connector
Terminal No. (Wire
color)
M105
1 (OR)
Ground
Approx. 5V
RJIA0563E