LIGHTING SYSTEM PROBLEM SYMPTOMS TABLE

Tech Tips

Use the table below to help determine the cause of problem symptoms. If multiple suspected areas are listed, the potential causes of the symptoms are listed in order of probability in the "Suspected Area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.

Headlight and Taillight (for Halogen Headlight)
Symptom	Suspected Area	See page
One low beam headlight does not illuminate.	H-LP LH LO fuse or H-LP RH LO fuse	-
	Bulb	-
	Power distributor (Engine room junction block assembly)	Click here
	Harness or connector	-
Both left and right low beam headlights do not illuminate.	Headlight dimmer switch circuit	Click here
	Low beam headlight circuit	Click here
	Main body ECU (Multiplex network body ECU)	Click here
One high beam headlight does not illuminate.	H-LP LH HI fuse or H-LP RH HI fuse	-
	Bulb	-
	Power distributor (Engine room junction block assembly)	Click here
	Harness or connector	-
Both left and right high beam headlights do not illuminate.	Headlight dimmer switch circuit	Click here
	High beam headlight circuit	Click here
	Main body ECU (Multiplex network body ECU)	Click here
"High Flash" (passing function) headlight does not illuminate (high beam headlights are normal).	Headlight dimmer switch circuit	Click here
	Main body ECU (Multiplex network body ECU)	Click here
One front parking light does not illuminate.	Harness or connector	-
One front parking light does not illuminate.	Headlight unit	Click here
One rear taillight does not illuminate.	Bulb	-
One rear taillight does not illuminate.	Harness or connector	-
One license plate light does not illuminate.	License plate light assembly	-
One license plate light does not illuminate.	Harness or connector	-
All of the lights (rear taillights, parking lights and license plate lights) do not illuminate.	TAIL fuse	-
	Headlight dimmer switch circuit	Click here
	Taillight relay circuit	Click here
	Main body ECU (Multiplex network body ECU)	Click here

Headlight and Taillight (for HID Headlight)
Symptom	Suspected Area	See page
One low beam headlight does not illuminate.	H-LP LH LO fuse or H-LP RH LO fuse	-
	Discharge headlight bulb	Click here
	Light control ECU	Click here
	Power distributor (Engine room junction block assembly)	Click here
	Headlight unit	Click here
	Harness or connector	-
Both left and right low beam headlights do not illuminate.	Headlight dimmer switch circuit	Click here
	Low beam headlight circuit	Click here
	Main body ECU (Multiplex network body ECU)	Click here
One high beam headlight does not illuminate.	H-LP LH HI fuse or H-LP RH HI fuse	-
	Bulb	-
	Power distributor (Engine room junction block assembly)	Click here
	Harness or connector	-
Both left and right high beam headlights do not illuminate.	Headlight dimmer switch circuit	Click here
	High beam headlight circuit	Click here
	Main body ECU (Multiplex network body ECU)	Click here
"High Flash" (passing function) headlight does not illuminate (high beam headlights are normal).	Headlight dimmer switch circuit	Click here
	Main body ECU (Multiplex network body ECU)	Click here
Discharge headlight bulb flickers.	Discharge headlight bulb	Click here
	Harness or connector	-
	Light control ECU	Click here
Discharge headlight bulb is dark.	Discharge headlight bulb	Click here
	Harness or connector	-
	Light control ECU	Click here
Discharge headlight bulb does not come on at intervals.	Discharge headlight bulb	Click here
	Harness or connector	-
	Light control ECU	Click here
One parking light does not illuminate.	Harness or connector	-
One parking light does not illuminate.	Headlight unit	Click here
One rear taillight does not illuminate.	Bulb	-
One rear taillight does not illuminate.	Harness or connector	-
One license plate light does not illuminate.	License plate light assembly	Click here
One license plate light does not illuminate.	Harness or connector	-
All of the lights (taillights, parking lights and license plate lights) do not illuminate.	TAIL fuse	-
	Headlight dimmer switch circuit	Click here
	Taillight relay circuit	Click here
	Main body ECU (Multiplex network body ECU)	Click here

Stop Light
Symptom	Suspected Area	See page
One side stop light does not illuminate.	Rear combination light assembly	Click here
One side stop light does not illuminate.	Harness or connector	-
High-mounted stop light does not illuminate.	High-mounted stop light assembly	Click here
High-mounted stop light does not illuminate.	Harness or connector	-
All of lights do not illuminate.	STOP fuse	-
	Stop light switch assembly	Click here
	Stop light control relay	Click here
	Harness or connector	-

Front Fog Light
Symptom	Suspected Area	See page
One side front fog light does not illuminate.	Bulb (for Halogen Fog Light)	-
	Fog light assembly (for LED Fog Light)	Click here
	Harness or connector	-
Both left and right front fog lights do not illuminate (taillights are normal).	FOG fuse	-
	Headlight dimmer switch circuit	Click here
	Front fog light circuit	Click here
	Main body ECU (Multiplex network body ECU)	Click here

Rear Fog Light
Symptom	Suspected Area	See page
One side rear fog light does not illuminate.	Bulb	-
One side rear fog light does not illuminate.	Harness or connector	-
Both left and right rear fog lights do not illuminate (taillights are normal).	RR FOG fuse	-
	Headlight dimmer switch circuit	Click here
	Rear fog light circuit	Click here
	Main body ECU (Multiplex network body ECU)	Click here

Back-up Light
Symptom	Suspected Area	See page
One back-up light does not illuminate.	Bulb	-
One back-up light does not illuminate.	Harness or connector	-
Both left and right back-up lights do not illuminate.	BK/UP LP NO. 2 fuse	-
	Park/neutral position switch (for U660F)	Click here
	Park/neutral position switch (for U760E)	Click here
	Harness or connector	-

Turn Signal Light
Symptom	Suspected Area	See page
Turn signal lights do not operate.	Check for DTCs	Click here
Side turn signal light does not operate.	Side turn signal light assembly	Click here
Side turn signal light does not operate.	Harness or connector	-
One turn signal light does not operate (except side turn signal lights).	Bulb	-
	Harness or connector	-

Hazard Warning Light
Symptom	Suspected Area	See page
Hazard warning lights do not operate.	HAZ fuse	-
	GAUGE NO. 1 fuse	-
	Hazard warning switch	Click here
	Turn signal flasher assembly	Click here
	Harness or connector	-

Automatic Light Control System
Symptom	Suspected Area	See page
Automatic light control system does not operate.	Check DTCs	Click here
	Headlight dimmer switch circuit	Click here
	IG signal circuit	Click here
	Main body ECU (Multiplex network body ECU)	Click here

Light Auto Turn-off System
Symptom	Suspected Area	See page
Light auto turn-off system does not operate.	Headlight dimmer switch circuit	Click here
	Door courtesy switch circuit	Click here
	IG signal circuit	Click here
	Main body ECU (Multiplex network body ECU)	Click here

Daytime Running Light System
Symptom	Suspected Area	See page
Daytime running light system does not operate.	Check CAN communication system	Click here
	Headlight dimmer switch circuit	Click here
	IG signal circuit	Click here
	Daytime running light relay circuit	Click here
	Main body ECU (Multiplex network body ECU)	Click here

Manual Headlight Beam Level Control System
Symptom	Suspected Area	See page
Headlight beam level control system does not operate.	H-LP RH-LO Fuse	-
	Headlight leveling switch	Click here
	Harness or connector	-
	Headlight unit	Click here

Automatic Headlight Beam Level Control System
Symptom	Suspected Area	See page
AFS OFF indicator light does not come on when turning the engine switch on (IG).	Combination meter assembly	Click here
	AFS ECU (Headlight swivel ECU assembly)	Click here
Headlight beam level control system does not operate.	Check fail-safe function	Click here
	Check DTCs	Click here
	AFS ECU (Headlight swivel ECU assembly)	Click here
Initialization cannot be performed (w/o Air Suspension System).	LVL terminal circuit	Click here
	Combination meter assembly	Click here
	AFS ECU (Headlight swivel ECU assembly)	Click here
Initialization cannot be performed (w/ Air Suspension System).	Combination meter assembly	Click here
	AFS ECU (Headlight swivel ECU assembly)	Click here

Note

Initialize the AFS ECU (headlight swivel ECU assembly) when the AFS ECU (headlight swivel ECU assembly) is replaced.
If the vehicle is not equipped with air suspension system, initialize the AFS ECU (headlight swivel ECU assembly) (set the zero point of the height control sensor in the AFS ECU (headlight swivel ECU assembly)) after the vehicle height changes due to replacement of suspension components or after performing such operations as removal and reinstallation or replacement of the rear height control sensor sub-assembly RH.

AFS
Symptom	Suspected Area	See page
AFS does not operate.	Check fail-safe function	Click here
	Check DTCs	Click here
	AFS ECU (Headlight swivel ECU assembly)	Click here
AFS OFF indicator light does not come on when turning the engine switch on (IG).	Harness or connector	-
	Combination meter assembly	Click here
	AFS ECU (Headlight swivel ECU assembly)	Click here
AFS on/off condition cannot be changed using steering pad switch assembly.	Steering pad switch assembly	Click here
	Harness or connector	-
	Combination meter assembly	Click here
	AFS ECU (Headlight swivel ECU assembly)	Click here

Note

Initialize the AFS ECU (headlight swivel ECU assembly) when the AFS ECU (headlight swivel ECU assembly) is replaced.

Welcome Light
Symptom	Suspected Area	See page
Welcome lights do not illuminate.	Wireless door lock control system	Click here
	Headlight dimmer switch circuit	Click here
	Main body ECU (Multiplex network body ECU)	Click here

Follow Me Home System
Symptom	Suspected Area	See page
Follow me home system does not operate.	IG signal circuit	Click here
	Headlight dimmer switch circuit	Click here
	Main body ECU (Multiplex network body ECU)	Click here