B1421

AIR CONDITIONING: AIR CONDITIONING SYSTEM: B1421: Solar Sensor Circuit (Passenger Side)

DTC B1421 - Solar Sensor Circuit (Passenger Side)

DESCRIPTION





The solar sensor is installed in the upper part of the instrument panel to detect the amount of solar radiation with a photodiode to control the heater and air conditioner "AUTO" function. It sends appropriate signals to the air conditioning amplifier. The output voltage of the solar sensor changes in accordance with the amount of solar radiation. As the amount increases, the voltage increases. As the amount decreases, the voltage decreases. The air conditioning amplifier reads voltage output from the solar sensor.






WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. READ VALUE USING TECHSTREAM
(a) Connect Techstream to DLC3.
(b) Turn the power switch ON (IG) and turn Techstream ON.
(c) Select the item below in the Data List, and read the display on Techstream.

Air conditioning amplifier





OK:
The display is as specified in the normal condition.

Result





C -- REPLACE AIR CONDITIONING AMPLIFIER
B -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
A -- Continue to next step.

2. CHECK AIR CONDITIONING AMPLIFIER (TS VOLTAGE)




(a) Remove the air conditioning amplifier with connectors still connected.
(b) Measure the voltage of the wire harness side connector.
Standard voltage:





HINT:
- As the inspection light is moved away from the sensor, the voltage increases.
- As the inspection light is moved closer to the sensor, the voltage decreases.
- Use an incandescent light for inspection. Bring it within 30 cm (11.8 in.) of the solar sensor.

Result





C -- REPLACE AIR CONDITIONING AMPLIFIER
B -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
A -- Continue to next step.

3. INSPECT SOLAR SENSOR




(a) Remove the solar sensor.
(b) Measure the resistance of the sensor.

- Connect the ohmmeter's positive (+) lead to terminal 2 and negative (-) lead to terminal 1 of the solar sensor.

Standard resistance:





NOTE: The connection procedure for using a digital tester such as an TOYOTA electrical tester is shown above. When using an analog tester, connect the positive (+) lead to terminal 1 and negative (-) lead to terminal 2 of the solar sensor.
HINT:
- As the inspection light is moved away from the sensor, the resistance increases.
- Use an incandescent light for inspection. Bring it within 30 cm (11.8 in.) of the solar sensor.

NG -- REPLACE SOLAR SENSOR
OK -- Continue to next step.

4. CHECK WIRE HARNESS (SOLAR SENSOR - AIR CONDITIONING AMPLIFIER)




(a) Disconnect the A10 solar sensor connector.
(b) Disconnect the A7 amplifier connector.
(c) Measure the resistance of the wire harness side connectors.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- REPLACE AIR CONDITIONING AMPLIFIER