B1419

AIR CONDITIONING: AIR CONDITIONING SYSTEM: B1419/19: Rear Room Temperature Sensor Circuit
B1419/19 - Rear Room Temperature Sensor Circuit

DESCRIPTION

The rear room temperature sensor LH is installed in the rear door trim board LH to detect the rear room temperature and control the heater and air conditioner "AUTO" mode. The resistance of the rear room temperature sensor changes in accordance with the rear room temperature for LH seat. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.

The rear door ECU LH sends the read signal to the air conditioning amplifier via the CAN communication line. The rear door ECU LH applies voltage (5 V) to the rear room temperature sensor and reads voltage changes as the resistance of the rear room temperature sensor changes. This sensor also sends the appropriate signals to the rear door ECU LH.

HINT
This circuit uses the CAN communication line. Before performing the inspection, check that the CAN communication system is functioning normally.





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. READ VALUE USING TECHSTREAM (REAR ROOM TEMPERATURE SENSOR)

(a) Use the Data List to check if the rear room temperature sensor for LH seat is functioning properly.

Air conditioner





OK:

The display is as specified in the normal condition.

NG -- INSPECT REAR ROOM TEMPERATURE SENSOR LH

OK -- REPLACE AIR CONDITIONING AMPLIFIER Removal

2. INSPECT REAR ROOM TEMPERATURE SENSOR LH





(a) Remove the rear room temperature sensor LH Removal.

(b) Measure the resistance according to the value(s) in the table below.

Standard resistance:





NOTICE:
Even slightly touching the sensor may change the resistance value. Be sure to hold the connector of the sensor.

HINT
As the temperature increases, the resistance decreases (see the graph).

NG -- REPLACE REAR ROOM TEMPERATURE SENSOR LH Removal
OK -- Continue to next step.

3. CHECK HARNESS AND CONNECTOR (REAR ROOM TEMPERATURE SENSOR LH - REAR DOOR ECU LH)





(a) Disconnect the Q9 rear room temperature sensor LH connector.

(b) Disconnect the O15 rear door ECU LH connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE REAR DOOR ECU LH Removal and Replacement