Lexus RX300 (MCU15). Manual - part 131

I04515

A

B

C

D

I04517

I04516

I04518

A

B

C

D

–

BODY ELECTRICAL

COMBINATION METER

BE–71

LEXUS RX300   (RM785E)

7.

INSPECT TACHOMETER RESISTANCE

(a)

Remove the meter cover, A/C and combination meter in-
tegrated ECU and combination meter circuit plate.

(b)

Measure the resistance between terminals with fixing
pointer to the stopper.

Tester connection

Resistance  (Ω)

A – B

140 – 185

C – D

130 – 175

If resistance value is not as specified, replace the meter.

8.

INSPECT FUEL RECEIVER GAUGE OPERATION (See
page DI–544)

(a)

Disconnect the connector from the main sender gauge.

(b)

Disconnect the battery terminal once then after 30 secs.,
reconnect the terminal.

(c)

Turn the ignition switch ON, check that the receiver gauge
needle indicates EMPTY.

(d)

Connect the main sender gauge.

(e)

Disconnect the connector from the sub sender gauge.

(f)

Disconnect the battery terminal once then after 30 secs.,
reconnect the terminal.

(g)

Turn the ignition switch ON, check that the receiver gauge
needle indicates EMPTY.

HINT:
Because of the silicon oil in the gauge, it will take a short time
for needle to stabilize.
If operation is not as specified, inspect the receiver gauge resis-
tance.
9.

INSPECT FUEL RECEIVER GAUGE RESISTANCE

(a)

Remove the meter cover, A/C and combination meter in-
tegrated ECU and combination meter circuit plate.

(b)

Measure the resistance between terminals with fixing
pointer to the stopper.

Tester connection

Resistance  (Ω)

A – B

140 – 185

C – D

130 – 175

If resistance value is not as specified, replace the receiver
gauge.

I04519

F

E

1

2

I04520

F

E

1

2

I04521

A

B

C

D

I01277

Battery

Ignition
Switch

Warning Light

Wire Harness Side

1

BE–72

–

BODY ELECTRICAL

COMBINATION METER

LEXUS RX300   (RM785E)

10.

INSPECT FUEL MAIN SENDER GAUGE RESISTANCE

Measure the resistance between terminals 1 and 2 for each
float position.

Float position mm (in.)

Resistance (Ω)

F: Approx. 26.6 (1.047) 

± 3 (0.12)

Approx. 2.0 

± 1.0

E: Approx. 

138.9 (5.468) ± 3 (0.12)

Approx. 38.7 

± 1.0

If resistance value is not as specified, replace the main sender
gauge.

11.

INSPECT FUEL SUB SENDER GAUGE RESISTANCE

Measure the resistance between terminals 1 and 2 for each
float position.

Float position mm (in.)

Resistance (Ω)

F: Approx. 2.4 (0.094) 

± 3 (0.12)

Approx. 2.0 

± 1.0

E: Approx. 

177.2 (6.976) ± 3 (0.12)

Approx. 71.3 

± 1.0

If resistance value is not as specified, replace the sub sender
gauge.

12.

INSPECT ENGINE COOLANT TEMPERATURE RE-
CEIVER GAUGE RESISTANCE

(a)

Remove the meter cover, A/C and combination meter in-
tegrated ECU and combination meter circuit plate.

(b)

Measure the resistance between terminals with fixing
pointer to the stopper.

Tester connection

Resistance  (Ω)

A – B

140 – 185

C – D

130 – 175

If resistance value is not as specified, replace the receiver
gauge.
HINT:
This circuit includes the diode.
If resistance value is not as specified, replace the receiver
gauge.
If resistance value is not as specified, replace the engine cool-
ant temperature sender gauge.

13.

INSPECT LOW OIL PRESSURE WARNING LIGHT

(a)

Disconnect the connector from the warning switch and
ground terminal on the wire harness side connector.

(b)

Turn the ignition switch ON and check that the warning
light lights up.

If the warning light does not light up, check the bulb circuit (See
page DI–551).

I01278

I01279

Battery

Ignition
Switch

Warning Light

I04522

OFF

ON

N01212

–

BODY ELECTRICAL

COMBINATION METER

BE–73

LEXUS RX300   (RM785E)

14.

INSPECT LOW OIL PRESSURE SWITCH CONTINUITY

(a)

Disconnect the connector from the switch.

(b)

Check that continuity exists between terminal and ground
with the engine stopped.

(c)

Check that no continuity exists between terminal and
ground with the engine running.

HINT:
Oil pressure should be over 24.5 kPa (0.25 kgf/cm

2

, 3.55 psi).

If operation is not as specified, replace the switch.

15.

INSPECT BRAKE WARNING LIGHT

(a)

Disconnect the connector from the brake fluid warning
switch.

(b)

Release the parking brake pedal.

(c)

Connect the terminals on the wire harness side of the lev-
el warning switch connector.

(d)

Start the engine, check that the warning light lights up.

If the warning light does not light up, check the bulb circuit (See
page DI–551).

16.

INSPECT BRAKE FLUID LEVEL WARNING SWITCH
CONTINUITY

(a)

Remove the reservoir tank cap and strainer.

(b)

Disconnect the connector.

(c)

Check that no continuity exists between the terminals with
the switch OFF (float up).

(d)

Use siphon, etc. to take fluid out of the reservoir tank.

(e)

Check that continuity exists between the terminals with
the switch ON (float down)

(f)

Pour the fluid back in the reservoir.

If operation is not as specified, replace the switch.
17.

INSPECT BRAKE FLUID LEVEL WARNING SWITCH
CIRCUIT

18.

INSPECT PARKING BRAKE SWITCH CONTINUITY

(a)

Check that continuity exists between the terminal and
switch body with the switch ON (switch pin released).

(b)

Check that no continuity exists between the terminal and
switch body with the switch OFF (switch pin pushed in).

If operation is not as specified, replace the switch or inspect
ground point.
19.

INSPECT PARKING BRAKE SWITCH CIRCUIT (See
page DI–596)

I04097

Battery

Ignition
Switch

Warning Light

Wire Harness Side

I08151

Wire Harness Side

I01286

Battery

Warning Light

BE–74

–

BODY ELECTRICAL

COMBINATION METER

LEXUS RX300   (RM785E)

20.

INSPECT REAR LIGHTS WARNING LIGHT

(a)

Disconnect the connector from the light failure sensor and
ground terminal 3 on the wire harness side connector.

(b)

Start the engine, check that the warning light lights up.

If the warning light does not light up, inspect the bulb or wire har-
ness.

21.

INSPECT LIGHT FAILURE RELAY CIRCUIT

Disconnect the connector from the relay and inspect the con-
nector on the wire harness side, as shown.

Tester connection

Condition

Specified  condition

1 – Ground

Constant

Continuity*

2 – Ground

Constant

Continuity*

9 – Ground

Constant

Continuity*

11 – Ground

Constant

Continuity

3 – Ground

Light control switch OFF

No voltage

3 – Ground

Light control switch TAIL or HEAD

Battery voltage

4 – Ground

Ignition switch LOCK or ACC

No voltage

4 – Ground

Ignition switch ON

Battery voltage

7 – Ground

Stop light switch OFF

No voltage

7 – Ground

Stop light switch ON

Battery voltage

8 – Ground

Ignition switch LOCK or ACC

No voltage

8 – Ground

Ignition switch ON

Battery voltage

*: There is resistance because this circuit is grounded through
the bulb.
If the circuit is as specified, replace the relay.
If the circuit is not as specified, inspect the circuits connected
to other parts.

22.

INSPECT OPEN DOOR WARNING LIGHT

Disconnect the connector from the door courtesy switch and
ground terminal 1 on the wire harness side, and check that the
warning light lights up.
If the warning light does not light up, check the bulb circuit (See
page DI–551).
23.

INSPECT DOOR COURTESY SWITCH CONTINUITY
AND CIRCUIT (See page BE–48)