Toyota Tundra Service Manual: Windshield Deicer does not Operate

Toyota Tundra Service Manual / Vehicle Interior / Window / Glass / Windshield Deicer System / Windshield Deicer does not Operate

DESCRIPTION

When the air conditioning control assembly (windshield deicer switch) turns is turned on, a windshield deicer activation request signal is sent via the LIN communication line to the air conditioning amplifier. Then the air conditioning amplifier operates the windshield deicer.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

HINT:

This circuit uses the LIN communication line. Before performing the inspection, check that the LIN communication system is functioning normally (see page ).

NOTICE:

Inspect the fuses for circuits related to this system before performing the following procedure.

PROCEDURE

1.

PERFORM ACTIVE TEST USING TECHSTREAM (WINDSHIELD DEICER RELAY ASSEMBLY)

(a) Select the Active Test using the Techstream to generate a control command, and then check that the windshield deicer operates (See page ).

Air Conditioner

Tester Display

Test Part

Control Range

Diagnostic Note

Deicer Relay (Front)

Windshield deicer relay assembly

ON or OFF

-

OK:

Windshield deicer relay assembly turns ON and OFF.

NG

GO TO STEP 3

OK

2.

CHECK AIR CONDITIONING CONTROL ASSEMBLY

(a) Temporarily replace the air conditioning control assembly with a new or normally functioning one (See page ).

(b) Check that the malfunction disappears.

OK:

Malfunction disappears.

OK

END (AIR CONDITIONING CONTROL ASSEMBLY IS DEFECTIVE)
NG

REPLACE AIR CONDITIONING AMPLIFIER

3.

INSPECT WINDSHIELD DEICER RELAY ASSEMBLY (DEICER)

(a) Remove the windshield deicer relay assembly (DEICER) from the engine room relay block, junction block.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

3 - 5

When battery voltage is not applied between terminals 1 and 2

10 kΩ or higher

When battery voltage is applied to terminals 1 and 2

Below 1 Ω
NG

REPLACE WINDSHIELD DEICER RELAY ASSEMBLY
OK

4.

CHECK HARNESS AND CONNECTOR (DEICER RELAY - AIR CONDITIONING AMPLIFIER AND BATTERY)

*a

Component without relay connected

(Engine Room Relay Block, Junction Block)

(a) Remove the windshield deicer relay assembly (DEICER) from the engine room relay block, junction block.

(b) Disconnect the J19 air conditioning amplifier connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

Windshield deicer relay assembly (DEICER) terminal 1 - Body ground

Ignition switch ON

11 to 14 V

Ignition switch OFF

Below 1 V

Windshield deicer relay assembly (DEICER) terminal 3 - Body ground

Always

11 to 14 V

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

Windshield deicer relay assembly (DEICER) terminal 2 - J19-40 (D)

Always

Below 1 Ω

Windshield deicer relay assembly (DEICER) terminal 2 or J19-40 (D) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

5.

CHECK HARNESS AND CONNECTOR (DEICER RELAY - WINDSHIELD DEICER WIRE)

(a) Remove the windshield deicer relay assembly (DEICER) from the engine room relay block, junction block.

(b) Disconnect the A23 windshield glass (windshield deicer wire) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

Windshield deicer relay assembly (DEICER) terminal 5 - A23-1 (B)

Always

Below 1 Ω

Windshield deicer relay assembly (DEICER) terminal 5 or A23-1 (B) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

6.

CHECK HARNESS AND CONNECTOR (WINDSHIELD DEICER WIRE - BODY GROUND)

*a

Front view of wire harness connector

(to Windshield Deicer Wire)

(a) Disconnect the windshield glass (windshield deicer wire) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A23-2 (E) - Body ground

Always

Below 1 Ω
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

7.

CHECK HARNESS AND CONNECTOR (WINDSHIELD DEICER POWER SOURCE)

*a

Front view of wire harness connector

(to Windshield Deicer Wire)

(a) Disconnect the windshield glass (windshield deicer wire) connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

A23-1 (B) - A23-2 (E)

Ignition switch ON, windshield deicer switch on

11 to 14 V

Ignition switch ON, windshield deicer switch off

Below 1 V
OK

REPLACE WINDSHIELD GLASS

NG

REPLACE AIR CONDITIONING AMPLIFIER

    Terminals Of Ecu

    Windshield Glass

    See More:

    Toyota Tundra Service Manual > Occupant Classification System: Front Occupant Classification Sensor RH Circuit Malfunction (B1781)
    DESCRIPTION The front occupant detection sensor RH circuit consists of the occupant classification ECU and the front occupant detection sensor RH. DTC B1781 is set when a malfunction is detected in the front occupant detection sensor RH circuit. DTC Code DTC Detection Condition Trouble Area B1781 On ...

    Toyota Tundra Owners Manual

    Toyota Tundra Service Manual

    © 2025 Copyright www.ttundra.com
    0.0294