Lexus RX300 (MCU15). Manual — part 134

BE0HE–13

I19140

Ignition Switch

Power Window Master Switch

Power Window Switch

Power Window Motor

Body ECU

Rear LH Door
ECU

Power Window Switch

Power Window Motor

Rear RH Door ECU

Power Window Switch

LHD:

RHD:

Power Window Motor

Power Window Switch

Body ECU

Power Window Master Switch

–

BODY ELECTRICAL

POWER WINDOW CONTROL SYSTEM

BE–83

LEXUS RX300 (RM785E)

LOCATION

BE0UG–03

I07405

1

15

I19125

14

BE–84

–

BODY ELECTRICAL

POWER WINDOW CONTROL SYSTEM

LEXUS RX300 (RM785E)

INSPECTION

1.

INSPECT ONE TOUCH POWER WINDOW SYSTEM/
CURRENT OF CIRCUIT (Using an ammeter)

(a)

Disconnect the connector from the power window master
switch.

(b)

Connect the positive (+) lead from the ammeter to termi-
nal 1 on the wire harness side connector and the negative
(–) lead to negative (–) terminal of the battery.

(c)

Connect the positive (+) lead from the battery to terminal
15 on the wire harness side connector.

(d)

As the window goes down, check that the current flow is
approximately 7 A.

(e)

Check that the current increases up to approximately
14.5 A or more when the window stops going down.

HINT:
The PTC opens some 4 – 90 seconds after the window stops
going down, so that check must be made before the PTC oper-
ates.
If the operation is as specified, replace the master switch.

2.

INSPECT ONE TOUCH POWER WINDOW SYSTEM/
CURRENT OF CIRCUIT (Using an ammeter with a cur-
rent–measuring probe)

(a)

Remove the power window master switch with connec-
tors connected.

(b)

Attach a current–measuring probe to terminal 14 of the
wire harness.

(c)

Turn the ignition switch ON and set the power window
switch in the down position.

(d)

As the window goes down, check that the current flow is
approximately 7 A.

(e)

Check that the current increases up to approximately
14.5 A or more when the window stops going down.

HINT:
The PTC opens some 4 – 90 seconds after the window stops
going down, so that check must be made before the PTC oper-
ates.
If operation is as specified, replace the master switch.

I08152

I08153

2

3

I01200

2

1

3

5

2

5

1

3

I04535

2

1

–

BODY ELECTRICAL

POWER WINDOW CONTROL SYSTEM

BE–85

LEXUS RX300 (RM785E)

3.

INSPECT POWER WINDOW SWITCH CONTINUITY

Switch position

Tester connection

Specified condition

UP AUTO

3 – 4, 3 – 6

Continuity

UP

3 – 6

Continuity

OFF

–

No continuity

DOWN

5 – 6

Continuity

DOWN AUTO

4 – 6, 5 – 6

Continuity

If continuity is not as specified, replace the switch.
4.

INSPECT POWER WINDOW SWITCH CIRCUIT
Rear LH side: (See page DI–657)
Rear RH side: (See page DI–674)

5.

INSPECT POWER WINDOW SWITCH ILLUMINATION

Connect the positive (+) lead from the battery to terminal 3 and
the negative (–) lead to terminal 2, and check that the indicator
light lights up.
If operation is not as specified, replace the switch.

6.

INSPECT POWER MAIN RELAY CONTINUITY

Condition

Tester connection

Specified condition

Constant

1 – 2

Continuity

Apply B+ between

terminals 1 and 2.

3 – 5

Continuity

If continuity is not as specified, replace the relay.
7.

INSPECT POWER MAIN RELAY CIRCUIT
(See page BE–18)

8.

INSPECT DRIVER’S (LHD)/PASSENGER’S (RHD)
DOOR POWER WINDOW MOTOR OPERATION

(a)

Connect the positive (+) lead from the battery to terminal
1 and the negative (–) lead to terminal 2, and check that
the motor turns clockwise.

I04536

2

1

I04537

1

2

I04538

1

2

I04539

1

3

I04540

1

3

BE–86

–

BODY ELECTRICAL

POWER WINDOW CONTROL SYSTEM

LEXUS RX300 (RM785E)

(b)

Reverse the polarity, check that the motor turns counter-
clockwise.

If operation is not as specified, replace the motor.
9.

INSPECT DRIVER’S (LHD)/PASSENGER’S (RHD)
DOOR POWER WINDOW MOTOR CIRCUIT
(See page DI–614)

10.

INSPECT PASSENGER’S (LHD)/DRIVER’S (RHD)
DOOR POWER WINDOW MOTOR OPERATION

(a)

Connect the positive (+) lead from the battery to terminal
1 and the negative (–) lead to terminal 2, and check that
the motor turns clockwise.

(b)

Reverse the polarity, check that the motor turns counter-
clockwise.

If operation is not as specified, replace the motor.
11.

INSPECT PASSENGER’S (LHD)/DRIVER’S (RHD)
DOOR POWER WINDOW MOTOR CIRCUIT
(See page DI–636)

12.

INSPECT REAR LH DOOR POWER WINDOW MOTOR
OPERATION

(a)

Connect the positive (+) lead from the battery to terminal
3 and the negative (–) lead to terminal 1, and check that
the motor turns clockwise.

(b)

Reverse the polarity, check that the motor turns counter-
clockwise.

If operation is not as specified, replace the motor.