B1436

AIR CONDITIONING SYSTEM: B1436/36: Air Mix Damper Position Sensor Circuit (Driver Side)

DTC B1436/36 - Air Mix Damper Position Sensor Circuit (Driver Side)

DESCRIPTION





This sensor detection the position of the air mix control servo motor (air outlet damper) and sends the appropriate signals to the A/C amplifier assembly. The position sensor is built in the air mix control servo motor. The position sensor resistance changes as the air mix control arm moves.
It outputs voltage (5 V) that is input to terminal 1 (VZ) and terminal 3 (PT) via the variable resistor, and then to the A/C amplifier assembly. The A/C amplifier assembly reads the arm position with the input voltage from the position sensor.






WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. READ VALUE OF TECHSTREAM
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch ON and push the Techstream main switch on.
(c) Select the item below in the DATA LIST, and read the display on the Techstream.

Air Conditioner





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






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





(a) Remove the A/C amplifier with the connectors still connected.
(b) Change the set temperature to activate the air mix control servo motor.
(c) Measure the voltage according to the value(s) in the table below.
Voltage:





HINT: As the set temperature increases, the voltage decreases gradually without interruption.

Result:






C -- REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY
B -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
A -- Continue to next step.
3. INSPECT AIR MIX CONTROL SERVO MOTOR





(a) Remove the air mix control servo motor.
(b) Disconnect the connector from the air mix control servo motor.
(c) Measure the resistance according to the value(s) in the table below.
Resistance:





(d) Measure the resistance according to the value(s) in the table below.
Resistance:










(e) As the air mix control servo motor moves from the COOL side to HOT side, the resistance decreases gradually without interruption.
HINT: For details regarding operation of the servo motor B1446.

NG -- REPLACE AIR MIX CONTROL SERVO MOTOR
OK -- Continue to next step.
4. CHECK HARNESS AND CONNECTOR (AIR MIX CONTROL SERVO MOTOR - A/C AMPLIFIER ASSEMBLY)





(a) Disconnect the connector from the A/C amplifier assembly.
(b) Measure the resistance according to the value(s) in the table below.
Resistance:






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