Toyota 4Runner: Meter Illumination is Always Dark

Toyota 4Runner Service Manual / Vehicle Interior / Meter / Gauge / Display / Meter / Gauge System / Meter Illumination is Always Dark

DESCRIPTION

This inspection is only for vehicles with automatic light control.

The meter CPU receives signals from this circuit to adjust the illumination of the meter, instrument panel and accessory meter assembly. The meter CPU sets the illumination level based on the user operation of the light control rheostat.

HINT:

The meter illumination level can be adjusted by rotating the light control rheostat dial up and down.
The meter illumination dims when the light control switch is turned to the tail or head position at night.
Setting the meter illumination to maximum brightness cancels the above dimming of the meter illumination.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

HINT:

Setting the meter illumination to minimum brightness turns off the meter illumination when the light control switch is changed to the tail or head position, or changed to the AUTO position at night.

PROCEDURE

1.	CHECK CAN COMMUNICATION SYSTEM

(a) Check if a CAN communication DTC is output (See page ).

Result

Result	Proceed to
CAN communication DTC is not output	A
CAN communication DTC is output	B

GO TO CAN COMMUNICATION SYSTEM

2.	CHECK DTC (LIGHT SENSOR CIRCUIT)

(a) Check if DTC B1244 is output (See page ).

Result

Result	Proceed to
B1244 is not output	A
B1244 is output	B

GO TO LIGHTING SYSTEM

3.	CHECK OPERATION (HEATER CONTROL PANEL)

(a) Turn the ignition switch to ON.

(b) Turn the light control switch to the tail, head or AUTO position.

(d) Check the heater control panel illumination.

Result

Result	Proceed to
Heater control panel illumination does not operate normally	A
Heater control panel illumination operates normally	B

HINT:

Both the heater control panel and combination meter assembly illumination dim according to the dimmer signal. Therefore, when only the meter illumination is always dark, there may be a malfunction in the combination meter assembly.

REPLACE COMBINATION METER ASSEMBLY

4.	CHECK OPERATION (AUTOMATIC LIGHT CONTROL SYSTEM)

(a) Turn the ignition switch to ON.

(b) Turn the light control switch to the AUTO position.

(d) Check the taillights and low beam headlights.

OK:

The taillights and low beam headlights come on.

(e) Uncover the automatic light control sensor.

(f) Check the low beam headlights and taillights.

OK:

The taillights and low beam headlights go off.

Result

Result	Proceed to
Automatic light control system operates normally	A
Automatic light control system does not operate normally	B

GO TO LIGHTING SETTING

5.	REPLACE MAIN BODY ECU

(a) Replace the main body ECU with a new or normally functioning one (See page ).

OK:

The operation of the combination meter assembly returns to normal.

HINT:

The meter CPU controls the meter illumination based on an auto dimmer signal from the main body ECU. When the meter illumination is always dark (very dim), it may be due to the main body ECU sending an auto dimmer signal to the meter CPU because of a malfunction in the main body ECU.

END

REPLACE COMBINATION METER ASSEMBLY

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