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:
Camshaft Position Sensor "A" Circuit
DESCRIPTION
The intake camshaft's Variable Valve Timing (VVT) sensor (G signal) consists
of a magnet and MRE
(Magneto Resistance Element).
The VVT camshaft drive gear has a sensor plate with 3 teeth on its outer
circumference. When the gear
rotates, changes occur in the air gaps betwee ...
Short in Front Passenger Side Squib 2nd Step
Circuit
DTC B1185/57 Short in Front Passenger Side Squib 2nd Step
Circuit
DESCRIPTION
The front passenger side squib 2nd step circuit consists of the center airbag
sensor assembly and the
front passenger airbag assembly.
The circuit instructs the SRS to deploy when deployment conditions are met.
...
System description
1. Radio and navigation assembly outline
Conventionally, 2 separate devices, a "radio and
display" and a "navigation ECU" are used. This
model has adopted a new type, combining these
devices into a single unit.
2. Navigation system outline
Vehicle ...
