B1417

HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM: B1417/17: Rear Evaporator Temperature Sensor Circuit
B1417/17 - Rear Evaporator Temperature Sensor Circuit

DESCRIPTION

The No. 2 air conditioning harness assembly (rear evaporator temperature sensor) is installed on the evaporator in the rear air conditioning unit to detect the cooled air temperature that has passed through the evaporator and to control the rear air conditioning. It sends signals to the air conditioning amplifier assembly. The signals change in accordance with the resistance of the No. 2 air conditioning harness assembly (rear evaporator temperature sensor). As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases. The air conditioning amplifier assembly applies a voltage (5 V) to the No. 2 air conditioning harness assembly (rear evaporator temperature sensor) and reads voltage changes as the resistance of the No. 2 air conditioning harness assembly (rear evaporator temperature sensor) changes. This sensor is used for frost prevention.





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

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

(a) Use the Data List to check if the rear evaporator temperature sensor is functioning properly Scan Tool Testing and Procedures.

Air Conditioner





OK:

The display is as specified in the normal condition column.

Result





C -- INSPECT NO. 2 AIR CONDITIONING HARNESS ASSEMBLY (REAR EVAPORATOR TEMPERATURE SENSOR)

B -- REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Removal

A -- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Symptom Related Diagnostic Procedures

2. INSPECT NO. 2 AIR CONDITIONING HARNESS ASSEMBLY (REAR EVAPORATOR TEMPERATURE SENSOR)

(a) Remove the No. 2 air conditioning harness assembly (rear evaporator temperature sensor) Disassembly.





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

Standard Resistance:





Text in Illustration





NOTICE:
* Even slightly touching the sensor may change the resistance value. Be sure to hold the connector of the sensor.
* When measuring, the sensor temperature must be the same as the ambient temperature.

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

NG -- REPLACE NO. 2 AIR CONDITIONING HARNESS ASSEMBLY (REAR EVAPORATOR TEMPERATURE SENSOR) Disassembly
OK -- Continue to next step.

3. CHECK HARNESS AND CONNECTOR (REAR EVAPORATOR TEMPERATURE SENSOR - AIR CONDITIONING AMPLIFIER)

(a) Disconnect the Q13 harness connector.

(b) Disconnect the G12 amplifier 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 AIR CONDITIONING AMPLIFIER ASSEMBLY Removal