Lexus RX300 (MCU15). Service manual - part 119

I04489

–

BODY ELECTRICAL

POWER SOURCE

BE–23

LEXUS RX300   (RM785E)

GAUGE

32 – Ground

IG switch ON

Battery voltage

RR WIP

33 – Ground

IG switch ON

Battery voltage

STOP

36 – Ground

Constant

Battery voltage

DBD

37 – Ground

Constant

Battery voltage

SEAT HTR

39 – Ground

Constant

Battery voltage

STARTER

41 – Ground

IG switch START

Battery voltage

WASHER

43 – Ground

IG switch ON

Battery voltage

FR DEF

48 – Ground

Constant

Battery voltage

SRS–B

49 – Ground

Constant

Battery voltage

TAIL

52 – Ground

Light control switch TAIL or HEAD

Battery voltage

PANEL

54 – Ground

Light control switch TAIL or HEAD

Battery voltage

(b)

Remove the relay from the instrument junction block and inspect the connector on the junction block
side.

Relay

Tester connection

Condition

Specified condition

TAILLIGHT

1 – Ground

2 – Ground

4 – Ground

Constant

Light Control switch TAIL or HEAD

Constant

Battery voltage

Continuity

Battery voltage

I04490

BE–24

–

BODY ELECTRICAL

POWER SOURCE

LEXUS RX300   (RM785E)

FOG

5 – Ground

7 – Ground

Light control switch TAIL

Constant

Battery voltage

Battery voltage

ACC

9 – Ground

10 – Ground

11 – Ground

12 – Ground

IG switch ACC or ON

Constant

Constant

Constant

Battery voltage

Continuity

Continuity

Battery voltage

If the circuit is as specified, inspect the circuit connected to other parts.

6.

INSPECT RELAY BLOCK NO. 1 CIRCUIT

Remove the relay from the relay block No. 1 and inspect the connector on the relay block side.

Relay

Tester connection

Condition

Specified condition

CIRCUIT OPENING

1 – Ground

5 – Ground

IG switch ON

IG switch ON

Battery voltage

Battery voltage

REAR FOG

7 – Ground

LIGHT

9 – Ground

Light control switch TAIL 

Light control switch TAIL

Battery voltage

Battery voltage

MIRROR HEATER

10 – Ground

12 – Ground

IG switch ON

Constant

Battery voltage

Battery voltage

If the circuit is as specified, inspect the circuit connected to other parts.

BE01L–14

I07352

Ignition Switch

Key Unlock Warning Switch

–

BODY ELECTRICAL

IGNITION SWITCH AND KEY UNLOCK WARNING 
SWITCH

BE–25

LEXUS RX300   (RM785E)

IGNITION SWITCH AND KEY UNLOCK WARNING SWITCH

LOCATION

BE0H4–05

I01256

1

2

3

4

5

6

7

8

LOCK

ACC

ON

START

I04031

From Back Side

LOCK

ACC

ON

START

BE–26

–

BODY ELECTRICAL

IGNITION SWITCH AND KEY UNLOCK WARNING 
SWITCH

LEXUS RX300   (RM785E)

INSPECTION

1.

INSPECT IGNITION SWITCH CONTINUITY

Switch position

Tester connection

Specified condition

LOCK

–

No continuity

ACC

2 – 3

Continuity

ON

2 – 3 – 4

6 – 7

Continuity

START

1 – 2 – 4

6 – 7 – 8

Continuity

If continuity is not as specified, replace the switch.

2.

INSPECT IGNITION SWITCH CIRCUIT

Connect the switch connector and inspect the connector on
wire harness side from the back side, as shown.

Tester connection

Condition

Specified condition

2 – Ground

Constant

Battery voltage

3 – Ground

Ignition switch ACC or ON

Battery voltage

4 – Ground

Ignition switch ON

Battery voltage

6 – Ground

Ignition switch ON or START

Battery voltage

7 – Ground

Constant

Battery voltage

8 – Ground

Ignition switch START

Battery voltage

If circuit is not as specified, inspect the circuits connected to oth-
er parts.