Sunload Sensor Circuit
Sunload Sensor CircuitCOMPONENT DESCRIPTION
Sunload Sensor
The sunload sensor is located on the passenger side 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 INPUT PROCESS
The unified meter and A/C amp. also includes a processing circuit which averages the variations in detected sunload over a period of time. This prevents drastic swings in the ATC 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 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 ATC 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 accordingly.
Diagnostic Procedure For Sunload Sensor (Step 1):
Diagnostic Procedure For Sunload Sensor (Steps 2 - 4):
DIAGNOSTIC PROCEDURE FOR SUNLOAD SENSOR
SYMPTOM: Sunload sensor circuit is open or shorted. (25 or -25 is indicated on unified meter and A/C amp. as a result of conducting Self-diagnosis STEP-2.)
COMPONENT INSPECTION
Sunload Sensor
Measure voltage between unified meter and A/C amp. harness connector
M89 terminal 50 (O) and ground.
If NG, replace unified meter and A/C amp.
- When checking sunload sensor, select a place where sun shines directly on it.