Toyota Sienna Service Manual: IG Power Source Circuit
DESCRIPTION
The main power source is supplied to the A/C amplifier when the ignition switch is turned to the ON position.
The power source is used for operating the A/C amplifier and servo motor, etc.
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT: Start the engine before inspection. Check the IG1 relay or battery if the engine does not start.
1 INSPECT FUSE (HTR)
(a) Remove the HTR fuse from the driver side junction block.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance 
2 INSPECT A/C AMPLIFIER (IG - GND)
(a) Remove the A/C amplifier with its connectors still connected.
(b) Turn the ignition switch to the ON position.
(c) Measure the voltage according to the value(s) in the table below.
Standard voltage 
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
3 CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - BATTERY)
(a) Disconnect the connector from the A/C amplifier.
(b) Measure the voltage according to the value(s) in the table below.
Standard voltage
4 CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - BODY GROUND)
(a) Measure the resistance according to the value(s) in the table below.
Standard resistance 
REPLACE A/C AMPLIFIER
Rear Blower Motor Circuit
DESCRIPTION
Power to the rear blower motor is supplied from the battery via the RR A/C
relay.
The rear blower motor speed level varies between 0 and 31 based on the voltage
difference measured ...
ACC Power Source Circuit
DESCRIPTION
This circuit supplies power to the A/C amplifier and the illumination for the
clock.
WIRING DIAGRAM
INSPECTION PROCEDURE
1 INSPECT FUSE (ECU ACC)
(a) Remove the ECU ACC fuse fr ...
Other materials:
Rear Occupant Classification Sensor LH Collision
Detection
DTC B1787 Rear Occupant Classification Sensor LH Collision
Detection
DESCRIPTION
DTC B1787 is output when the occupant classification ECU receives a collision
detection signal sent by
the rear occupant classification sensor LH if an accident occurs.
DTC B1787 is also output when the front s ...
Data list / active test
1. DATA LIST
(a) While the intelligent tester is connected to the DLC3
with the ignition switch in the ON position, the ABS
data list can be displayed. Follow the prompts on
the tester screen to access the DATA LIST.
2. ACTIVE TEST
HINT:
Performing the ACTIVE TEST using the intelligent te ...
Installation
1. Install thermostat
(a) Install a new gasket to the thermostat.
(b) Install the thermostat with the jiggle valve facing up.
Hint:
the jiggle valve may be set within 10° on either side
of the prescribed position.
2. INSTALL WATER INLET
(a) Install the water inlet with the 2 nuts . ...
