Lexus RX300 (MCU15). Manual — part 336

TAIL

OFF

HEAD

OFF

Headlight switch
(Tail)

OFF

ON

Terminal

Switch position

(tester display)

Headlight switch
(Head)

OFF

ON

ON

Auto light switch

AUTO

OFF

OFF

OFF

OFF

OFF

ON

DI–576

–

DIAGNOSTICS

BODY CONTROL SYSTEM

LEXUS RX300 (RM785E)

INSPECTION PROCEDURE

HINT:
In case of using the hand–held tester, start the inspection from step 1 and in case of not using the hand–held
tester, start from step 2.

1

Check headlight control switch using hand–held tester.

PREPARATION:
Connect the hand–held tester to the DLC 3.
CHECK:
Check the headlight control switch using DATA LIST.
OK:

OK

Proceed to next circuit inspection shown on
problem symptoms table (See page DI–570).

NG

2

Check headlight control switch (See page BE–31).

NG

Replace the headlight control switch.

OK

–

DIAGNOSTICS

BODY CONTROL SYSTEM

DI–577

LEXUS RX300 (RM785E)

3

Check wireharness and connector between headlight control switch and Body
ECU.

NG

Repair or replace wireharness or connector.

OK

Proceed to next circuit inspection shown on
problem symptoms table
(See page DI–570).

I03065

Body ECU

H9
Hazard Switch

HAZ

LG–B

7

11

B8

B1

DI–578

–

DIAGNOSTICS

BODY CONTROL SYSTEM

LEXUS RX300 (RM785E)

Hazard switch circuit

CIRCUIT DESCRIPTION

Body ECU activates the flasher relay during warning of the theft deterrent system and flashers the hazard.

WIRING DIAGRAM

DI1OM–05

–

DIAGNOSTICS

BODY CONTROL SYSTEM

DI–579

LEXUS RX300 (RM785E)

INSPECTION PROCEDURE

HINT:
In case of using the hand–held tester, start the inspection from step 1 and incase of not using the hand–held
tester, start from step 2.

1

Check hazard operation using hand–held tester.

PREPARATION:
Connect the hand–held tester to the DLC 3.
CHECK:
Check that the hazard can operate in an ACTIVE TEST.

OK

Proceed to next circuit inspection shown on
problem symptoms table (See page DI–570).

NG

2

Check hazard switch (See page BE–44).

NG

Replace the hazard switch.

OK

3

Check wireharness and connector between hazard switch and Body ECU.

NG

Repair or replace wireharness or connector.

OK

Proceed to next circuit inspection shown on
problem symptoms table
(See page DI–570).