Toyota Sienna Service Manual: Rear Air Conditioning Relay Circuit
DESCRIPTION
The RR A/C relay is switched on by signals from the A/C amplifier. It supplies power to the rear blower motor.
WIRING DIAGRAM
INSPECTION PROCEDURE
1 INSPECT RELAY (RR A/C)
(a) Remove the RR A/C relay from the No. 3 relay block.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance 
2 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
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
Rear Air Conditioning Control Panel Circuit
DESCRIPTION
This is the rear A/C system control signal circuit as well as the power
supply circuit of the rear A/C control
assembly.
Pulse signals regarding rear A/C control panel switch operat ...
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 ...
Other materials:
Reverse Signal Circuit
DESCRIPTION
The radio and navigation assembly receives a reverse signal from the
park/neutral position switch and
information about the GPS antenna, and then adjusts vehicle position.
WIRING DIAGRAM
INSPECTION PROCEDURE
1 INSPECT RADIO AND NAVIGATION ASSEMBLY
Disconnect the radio ...
Back-up Power Source Circuit
DESCRIPTION
This is the back-up power source for the A/C amplifier. Power is supplied
even when the ignition switch is
off and is used for diagnostic trouble code memory, etc.
WIRING DIAGRAM
INSPECTION PROCEDURE
1 INSPECT FUSE (ECU-B)
(a) Remove the ECU-B fuse from the engine room juncti ...
Diagnosis system
1. DESCRIPTION
When troubleshooting a vehicle with the diagnosis
system, the only difference from the usual
troubleshooting procedure is connecting the intelligent
tester to the vehicle and reading various data output from
the vehicle's clearance warning ECU.
The clearance warning ECU record ...
