Toyota Tundra Service Manual: Blower Motor Circuit

Toyota Tundra Service Manual / Vehicle Interior / Air Conditioning / Air Conditioning System(for Automatic Air Conditioning System) / Blower Motor Circuit

DESCRIPTION

The blower motor is operated by signals from the air conditioning amplifier. Blower motor speed signals are transmitted by changes in the duty ratio.

Duty Ratio:

The duty ratio is the ratio of the blower motor OFF time (B) to the total of the blower motor ON and OFF time (A + B).

The blower motor controller controls the blower motor speed.

WIRING DIAGRAM

PROCEDURE

1.	PERFORM ACTIVE TEST USING TECHSTREAM (BLOWER MOTOR)

(a) Select the Active Test, using the Techstream to generate a control command, and then check that the blower motor operates.

Air Conditioner

Tester Display	Test Part	Control Range	Diagnostic Note
Blower Motor	Blower motor	Min.: 0, Max.: 31	-

Result

Result	Proceed to
NG (blower motor does not operate)	A
NG (blower motor operates but does not change speed)	B
OK	C

GO TO STEP 5

PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

2.	INSPECT FUSE (HTR)

(a) Remove the HTR H-fuse from the engine room relay block.

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

Standard resistance:

Tester Connection	Condition	Specified Condition
HTR H-fuse	Always	Below 1 Ω

REPLACE FUSE

3.	CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - BATTERY AND BODY GROUND)

(a) Disconnect the J32 blower motor connector.

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

Standard resistance:

Tester Connection	Condition	Specified Condition
J32-1 (GND) - Body ground	Always	Below 1 Ω

Standard voltage:

Tester Connection	Condition	Specified Condition
J32-3 (+B) - Body ground	Always	11 to 14 V

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.	CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - BLOWER MOTOR)

(a) Disconnect the J19 air conditioning amplifier connector.

(b) Disconnect the J32 blower motor connector.

Standard resistance:

Tester Connection	Condition	Specified Condition
J19-23 (BLW) - J32-2 (S1)	Always	Below 1 Ω
J19-23 (BLW) or J32-2 (S1) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

5.	CHECK BLOWER MOTOR (S1 VOLTAGE)

(a) Disconnect the J19 air conditioning amplifier connector.

(b) Reconnect the J32 blower motor connector.

Standard voltage:

Tester Connection	Switch Condition	Specified Condition
J19-23 (BLW) - Body ground	Ignition switch ON	4.5 to 5.5 V

REPLACE BLOWER MOTOR

6.	CHECK AIR CONDITIONING AMPLIFIER (BLW VOLTAGE)

(a) Remove the air conditioning amplifier with its connectors still connected (see page ).

(b) Turn the ignition switch ON.

(d) Using an oscilloscope, check the waveform.

Standard:

Tester Connection

Tool Setting

Switch Condition

Specified Condition

J19-23 (BLW) - J19-14 (GND)

1 V/DIV., 500 μsec./DIV.

Ignition switch ON

Blower switch LO

Pulse generation

HINT:

Waveform varies with the blower level.

PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

REPLACE AIR CONDITIONING AMPLIFIER

Multiplex Communication Circuit (B1499/99)

Check Mode Procedure

See More:

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