Air Conditioning System (for Manual Air Conditioning System)

AIR CONDITIONING: AIR CONDITIONING SYSTEM (for Manual Air Conditioning System): B1417/17: Rear Evaporator Temperature Sensor Circuit
B1417/17 - Rear Evaporator Temperature Sensor Circuit

DESCRIPTION

The rear air conditioning harness (rear evaporator temperature sensor) is installed on the evaporator in the rear air conditioning unit to detect the temperature of the cooled air that has passed through the evaporator and to control the rear air conditioner. It sends signals to the air conditioning amplifier. The signals change in accordance with the resistance of the rear air conditioning harness (rear evaporator temperature sensor). As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases. The air conditioning amplifier applies a voltage (5 V) to the rear air conditioning harness (rear evaporator temperature sensor) and reads voltage changes as changes in the resistance of the rear air conditioning harness (rear evaporator temperature sensor). This sensor is used for frost prevention.





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. READ VALUE USING TECHSTREAM

(a) Connect Techstream to the DLC3.

(b) Turn the ignition switch on (IG) and turn Techstream main switch on.

(c) Select the item below in the Data List, and read the value displayed on Techstream.

Data List / Air Conditioner





OK:

The display is as specified in the normal condition column.

Result:





B -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE Air Conditioning System (for Manual Air Conditioning System)

C -- REPLACE AIR CONDITIONING AMPLIFIER Removal
A -- Continue to next step.

2. INSPECT REAR AIR CONDITIONING HARNESS (REAR EVAPORATOR TEMPERATURE SENSOR)

(a) Remove the rear air conditioning harness.





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

Standard resistance:





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

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

NG -- REPLACE REAR AIR CONDITIONING HARNESS
OK -- Continue to next step.

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

(a) Disconnect the N12 rear air conditioning harness connector.





(b) Disconnect the D38 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 Removal