Last Modified: 04-05-2023 6.11:8.1.0 Doc ID: RM100000000VKEW
Model Year Start: 2016 Model: Sienna Prod Date Range: [12/2015 -           ]
Title: WIPER / WASHER: WIPER AND WASHER SYSTEM(w/ Rain Sensor): Rain Sensor Circuit; 2016 - 2020 MY Sienna [12/2015 -        ]

Rain Sensor Circuit

DESCRIPTION

The windshield wiper relay assembly receives a signal from the rain sensor to control the auto wiper system.

WIRING DIAGRAM

PROCEDURE

1.

CHECK HARNESS AND CONNECTOR (WINDSHIELD WIPER RELAY ASSEMBLY - RAIN SENSOR)

(a) Disconnect the D78 windshield wiper relay assembly connector.

(b) Disconnect the T3 rain sensor connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

D78-8 (SIG) - T3-4 (SIG)

Always

Below 1 Ω

T3-4 (SIG) - Body ground

Always

10 kΩ or higher

D78-14 (PA1) - T3-3 (AUTO)

Always

Below 1 Ω

T3-3 (AUTO) - Body ground

Always

10 kΩ or higher

D78-25 (E) - T3-1 (ES)

Always

Below 1 Ω

T3-1 (ES) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

2.

INSPECT WINDSHIELD WIPER RELAY ASSEMBLY

(a) Reconnect the windshield wiper relay assembly connector.

(b) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

D78-8 (SIG) - D78-25 (E)

Ignition switch ON

7.7 to 8.3V

Text in Illustration

*a

Component with harness connected

(Windshield Wiper Relay Assembly)
NG

REPLACE WINDSHIELD WIPER RELAY ASSEMBLY

OK

3.

INSPECT RAIN SENSOR

(a) Reconnect the rain sensor connector.

(b) Connect an oscilloscope to the rain sensor connector.

(c) Check for pulses.

OK:

Tester Connection

Switch Condition

Specified Condition

T3-3 (AUTO) - T3-1 (ES)

Ignition switch ON

Pulse generation

Text in Illustration

*a

Component with harness connected

(Rain Sensor)
OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG

REPLACE RAIN SENSOR

(See page 2016 - 2017 MY Sienna [12/2015 - 11/2017]; WIPER / WASHER: RAIN SENSOR: REMOVAL 2018 - 2020 MY Sienna [11/2017 -        ]; WIPER / WASHER: RAIN SENSOR: REMOVAL )