Toyota Sienna Service Manual: Room Temperature Sensor Circuit
DESCRIPTION
This sensor detects the cabin temperature that is used as the basis for
temperature control and sends a
signal to the A/C amplifier. 
WIRING DIAGRAM 
INSPECTION PROCEDURE
1 READ VALUE OF INTELLIGENT TESTER
(a) Connect the intelligent tester to the DLC3.
(b) Turn the ignition switch to the ON position and turn the intelligent tester main switch on.
(c) Select the item below in the DATA LIST, and read the display on the intelligent tester.
DATA LIST / AIR CONDITIONER: 
OK: The display is as specified in the normal condition column.
Result 
2 INSPECT A/C ROOM TEMPERATURE SENSOR
(a) Remove the A/C room temperature sensor.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance 
NOTICE:
- Hold the sensor only by its connector. Touching the sensor may change the resistance value.
- When measuring, the sensor temperature must be the same as the room temperature.
HINT: As the temperature increases, the resistance decreases (see the graph).
3 CHECK HARNESS AND CONNECTOR (A/C ROOM TEMPERATURE SENSOR - A/C AMPLIFIER)
(a) Disconnect the connector from the A/C amplifier.
(b) Disconnect the connector from the A/C room temperature sensor.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance 
REPLACE A/C AMPLIFIER
Actuator check
1. ACTUATOR CHECK
(a) After entering the DTC check mode (Sensor Check
Mode), press the R/F switch.
(b) As each damper, motor and relay automatically
operate actuator check at 1-second interval ...
Ambient temperature sensor circuit
DTC B1412/12 Ambient Temperature Sensor Circuit
DESCRIPTION
The ambient temperature sensor is installed in front of the condenser to
detect the ambient temperature
which is used to control the ai ...
Other materials:
Removal
1. REMOVE REAR DOOR SCUFF PLATE LH
2. REMOVE REAR DOOR WEATHERSTRIP LH
3. REMOVE BACK DOOR WEATHERSTRIP
4. REMOVE BACK DOOR SCUFF PLATE
5. REMOVE QUARTER TRIM FRONT PANEL ASSEMBLY LH
6. REMOVE POWER POINT SOCKET ASSEMBLY
Release the 2 claw fittings and remove the power
point soc ...
Disassembly
1. REMOVE REAR SEAT LEG COVER LH
Remove the 2 screws and seat leg cover.
2. REMOVE REAR SEAT LEG COVER RH
Remove the 2 screws and seat leg cover.
3. REMOVE REAR SEAT LEG SIDE COVER LH
Remove the 2 screws and leg side cover.
4. REMOVE LH SEAT REAR SEAT LOCK COVE ...
Terminals of ECU
1. CHECK POWER BACK DOOR ECU
Disconnect the P13 and P14 ECU connectors, and
check the voltage and resistance of each terminal of
the wire harness side connectors
If the result is not as specified, there may be a
malfunction on the wire harness side.
Reconnect the ECU co ...