Diagnosis Procedure

SUNLOAD SENSOR


Description


COMPONENT DESCRIPTION

Sunload Sensor
The sunload sensor (1) is located on the driver's side front defroster grille. 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 unified meter and A/C amp.






Sunload Sensor Circuit






SUNLOAD INPUT PROCESS
The unified meter and A/C amp. also equips a processing circuit which averages the variations in detected sunload over a period of time. This prevents drastic swings in the air temperature control 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 varies whenever the trees obstruct the sunlight. The processing circuit averages 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 air temperature control system operation. On the other hand, shortly after entering a long tunnel, the system recognizes the change in sunload, and the system reacts accordingly.




SUNLOAD SENSOR


Diagnosis Procedure

1.CHECK VOLTAGE BETWEEN SUNLOAD SENSOR AND GROUND
1. Disconnect sunload sensor connector.
2. Turn ignition switch ON.
3. Check voltage between sunload sensor harness connector and ground.





Is the inspection result normal?
YES - GO TO 2.
NO - GO TO 4.
2.CHECK CIRCUIT CONTINUITY BETWEEN SUNLOAD SENSOR AND UNIFIED METER AND A/C AMP.
1. Turn ignition switch OFF.
2. Disconnect unified meter and A/C amp. connector.
3. Check continuity between sunload sensor harness connector and unified meter and A/C amp. harness connector.





Is the inspection result normal?
YES - GO TO 3.
NO - Repair harness or connector.
3.CHECK SUNLOAD SENSOR
1. Reconnect sunload sensor connector and unified meter and A/C amp. connector.
2. Check sunload sensor. Refer to Component Inspection.
Is the inspection result normal?
YES - Replace unified meter and A/C amp.
NO - Replace sunload sensor.
4.CHECK CIRCUIT CONTINUITY BETWEEN SUNLOAD SENSOR AND UNIFIED METER AND A/C AMP.
1. Turn ignition switch OFF.
2. Disconnect unified meter and A/C amp. connector.
3. Check continuity between sunload sensor harness connector and unified meter and A/C amp. harness connector.





4. Check continuity between sunload sensor harness connector and ground.





Is the inspection result normal?
YES - Replace unified meter and A/C amp.
NO - Repair harness or connector.