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:
Removal
1. DISCONNECT CABLE FROM NEGATIVE BATTERY
TERMINAL
2. REMOVE ROOF HEADLINING ASSEMBLY
HINT:
Refer to the instructions for REMOVAL of the ROOF
HEADLINING (See page IR-6).
3. REMOVE TIRE PRESSURE WARNING RECEIVER ASSEMBLY
(a) Remove the bolt.
(b) Disconnect the connector and remove the ...
Mass or Volume Air Flow Circuit
DESCRIPTION
The Mass Air Flow (MAF) meter is a sensor that measures the amount of air
flowing through the throttle
valve. The ECM uses this information to determine the fuel injection time and to
provide appropriate airfuel
ratio. Inside the MAF meter, there is a heated platinum wire whic ...
Clearance warning ECU
COMPONENTS
REMOVAL
1. REMOVE FRONT DOOR SCUFF PLATE LH
2. REMOVE COWL SIDE TRIM BOARD LH
3. REMOVE INSTRUMENT PANEL FINISH PANEL SUBASSEMBLY LOWER LH
4. REMOVE NO. 1 INSTRUMENT PANEL SAFETY PAD INSERT SUB-ASSEMBLY
5. REMOVE CLEARANCE WARNING ECU
Disconnect each connector.
&nb ...
