Trouble Shooting: Notes

WARNING: This page is about a different car, the 2003 Lexus GS 430, 2003 Lexus GS 300, 2002 Lexus GS 430, and 2002 Lexus GS 300. However, it is still accessible from the selected car via links, so may be relevant.

Trouble shooting of a automatic headlight and lighting system complaint begins with verification of the customer problem. If problem occurs, go to step 3. If problem does not occur, go to next step.
If problem does not occur, review conditions under which problem occurred for customer and try to duplicate those conditions. For example, if the problem occurs on rainy days or during high humidity conditions, sprinkle water onto vehicle and see if malfunction occurs. DO NOT sprinkle water directly into engine compartment or onto electronic components. Visually inspect for signs of mechanical and electrical damage. Inspect for blown fuses and damaged relays. Inspect for loose or corroded connections, damaged wiring harnesses and/or switches. Check for a broken or partially broken wire inside insulation, which could cause system malfunction but prove good in a continuity/voltage check with system disconnected. Ensure any aftermarket electronic equipment is properly installed. If fault is found, repair as necessary.
This system uses the multiplex communication system so, check the diagnosis system of the multiplex communication system. See MULTIPLEX COMMUNICATION SYSTEM article under COMMUNICATION DEVICES in ACCESSORIES & EQUIPMENT.
Determine problem symptom. See AUTOMATIC HEADLIGHT & LIGHTING PROBLEM SYMPTOMS table.
After problem has been identified and repaired, confirm repairs. After repairs have been completed, confirm that problem has been eliminated. Operate system under same conditions recorded for original complaint. If problem is no longer present, repair has corrected problem. If problem is still present, further diagnosis and repair is required.

AUTOMATIC HEADLIGHT & LIGHTING PROBLEM SYMPTOMS

Symptom

Suspected Area ⁽¹⁾

Fog Light System

Fog Light Does Not Light Up With Light Control Switch HEAD (Headlight Normal)

⁽²⁾⁽³⁾⁽⁴⁾⁽⁵⁾⁽⁶⁾

Fog Light Does Not Light Up With Light Control Switch HEAD (Headlight Does Not Light)

⁽⁷⁾⁽⁵⁾

Only One Light Does Not Light Up

⁽⁸⁾⁽⁵⁾

Headlight & Taillight ⁽⁹⁾

Automatic Light Control System Does Not Operate

⁽¹⁰⁾⁽¹¹⁾⁽¹²⁾⁽⁵⁾⁽⁶⁾

Auto Turn-Off System Does Not Operate When Driver's Door Is Opened

⁽¹²⁾

Auto Turn-Off System: Headlight & Taillight Do Not Come On

⁽⁶⁾⁽⁵⁾

Auto Turn-Off System: Headlight & Taillight Stay On

⁽⁶⁾⁽⁵⁾

Only One Headlight Comes On (CANADA)

⁽¹³⁾⁽¹⁴⁾⁽⁸⁾⁽¹⁵⁾⁽⁵⁾

Only One Headlight Comes On (USA)

⁽⁸⁾⁽¹⁵⁾⁽⁵⁾

LO-Beam Does Not Light (All)

⁽¹⁶⁾⁽¹⁵⁾⁽⁵⁾

LO-Beam Does Not Light (One Side)

⁽⁸⁾⁽¹⁷⁾⁽¹⁵⁾⁽⁵⁾

HI-Beam Does Not Light (CANADA - All)

⁽¹⁸⁾⁽¹⁴⁾⁽⁵⁾

HI-Beam Does Not Light (CANADA - One Side)

⁽⁸⁾⁽¹⁹⁾⁽²⁰⁾⁽⁵⁾

HI-Beam Does Not Light (USA - All)

⁽¹⁸⁾⁽⁵⁾

HI-Beam Does Not Light (USA - One Side)

⁽⁸⁾⁽¹⁹⁾⁽⁵⁾

Flash Does Not Light (CANADA)

⁽¹⁸⁾⁽¹⁴⁾⁽⁵⁾

Flash Does Not Light (USA - All)

⁽¹⁹⁾⁽¹⁸⁾⁽¹⁵⁾⁽⁵⁾

Flash Does Not Light (USA - One Side)

⁽⁸⁾⁽¹⁵⁾⁽⁵⁾

Headlight Does Not Come On (CANADA)

⁽¹⁶⁾⁽¹⁴⁾⁽¹³⁾⁽¹⁸⁾⁽¹¹⁾⁽⁵⁾⁽¹⁵⁾⁽⁸⁾

Headlight Does Not Come On (USA - All)

⁽¹⁶⁾⁽¹¹⁾⁽¹⁵⁾⁽⁵⁾

Headlight Does Not Come On (USA -One Side)

⁽⁸⁾⁽¹⁵⁾⁽⁵⁾

Headlight Does Not Come On With Light Control Switch In HEAD (CANADA)

⁽¹¹⁾⁽¹⁵⁾⁽⁵⁾

Headlight Does Not Go Out With Light Control Switch In OFF (CANADA)

⁽¹⁶⁾⁽¹⁵⁾⁽⁵⁾

Headlight Does Not Come On With Engine Running & Light Control Switch In OFF (CANADA)

⁽²¹⁾⁽²²⁾⁽¹⁴⁾⁽¹³⁾⁽²³⁾⁽²⁴⁾⁽⁵⁾

Headlight Flickers

⁽⁸⁾⁽¹⁵⁾⁽⁵⁾

Headlight Is Dark

⁽⁸⁾⁽¹⁵⁾⁽⁵⁾

Only One Taillight Comes On (USA)

⁽⁸⁾⁽⁵⁾

Taillight Does Not Come On & Headlight Is Normal (USA)

⁽²⁵⁾⁽²²⁾⁽²⁶⁾⁽²⁷⁾⁽¹¹⁾⁽⁵⁾

Taillight Does Not Come On & Headlight Does Not Light (USA)

⁽¹¹⁾⁽⁵⁾

Taillight Does Not Come On With Light Control Switch In TAIL Or OFF (CANADA)

⁽²⁶⁾⁽¹¹⁾⁽⁵⁾

Rear Combination Light Does Not Come On (USA)

⁽²⁷⁾⁽⁵⁾⁽⁸⁾

Headlight Beam Level Control System

Beam Axis Is Not Controlled (Not Initialized) & Headlight Beam Level Control System Does Not Operate

⁽²⁸⁾⁽²⁹⁾⁽³⁰⁾⁽⁵⁾

Beam Axis Is Not Controlled (Initialized) & Headlight Beam Level Control System Does Not Operate

⁽³¹⁾⁽³⁰⁾⁽⁵⁾

Controlled Angle Of Headlight Is Unusual (Angle Is Controlled)

⁽³¹⁾⁽³⁰⁾⁽³²⁾⁽⁵⁾

Beam Axis Position Is Not Stable During Driving

⁽³³⁾⁽³²⁾⁽⁵⁾

Interior Light System

All Lights Do Not Come On

⁽³⁴⁾⁽⁶⁾

Light Does Not Come On When Driver's Or Passenger's Door Is Opened

⁽¹²⁾⁽⁵⁾

Light Does Not Come On When Rear-Right Or Rear-Left Door Is Opened

⁽³⁵⁾⁽⁵⁾

Only One Bulb Comes On

⁽⁸⁾

Illumination Does Not Fade Out When All Doors Are Closed

⁽¹²⁾⁽³⁵⁾⁽⁵⁾

Illumination Does Not Fade Out Immediately When Ignition Switch Is Turned To ACC Or ON Within 15 Seconds After All Doors Are Closed

⁽³⁶⁾⁽³⁷⁾⁽²²⁾⁽⁵⁾

Illumination Does Not Fade Out Immediately When All Doors Are Locked Within 15 Seconds After Closed

⁽³⁸⁾⁽⁵⁾

Interior Light (In Front Personal Light) Or Front Personal Light Does Not Light Up

⁽⁸⁾⁽³⁹⁾⁽⁵⁾

Rear Personal Light Does Not Light Up

⁽⁸⁾⁽⁴⁰⁾⁽⁵⁾

Vanity Light Does Not Light Up

⁽⁸⁾⁽⁴¹⁾⁽⁵⁾

Luggage Compartment Light Does Not Light Up

⁽⁸⁾⁽⁴²⁾⁽⁵⁾

Courtesy Light Does Not Light Up

⁽⁸⁾⁽¹²⁾⁽³⁵⁾⁽⁵⁾

⁽¹⁾	Perform test procedures in order listed under suspected area.

⁽²⁾	Check the FOG fuse (15-amp). See COMPONENT LOCATIONS .

⁽³⁾	Check the fog light relay. See STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT.

⁽⁴⁾	Check the fog light switch. See STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT.

⁽⁵⁾	Check the wire harness. See WIRING DIAGRAMS .

⁽⁶⁾	Check the body ECU No. 2. See PIN VOLTAGES under BODY CONTROL SYSTEMS article under COMMUNICATION DEVICES in ACCESSORIES & EQUIPMENT.

⁽⁷⁾	Check the other parts of the headlight system. See WIRING DIAGRAMS .

⁽⁸⁾	Check the bulb.

⁽⁹⁾	Inspect the bulb and light control ECU, replace them with the ones working normally and judge whether they work normally or not. Inspection information not provided by manufacturer. For replacement, see HEADLIGHT ASSEMBLY under REMOVAL & INSTALLATION.

⁽¹⁰⁾	Check the automatic light control sensor. See AUTOMATIC LIGHT CONTROL SENSOR CIRCUIT under CIRCUIT TESTS.

⁽¹¹⁾	Check the light control switch. See STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT.

⁽¹²⁾	Check the door courtesy switch. See DOOR COURTESY SWITCH CIRCUIT (FRONT) under CIRCUIT TESTS and DOOR COURTESY SWITCH (FRONT) under COMPONENT TESTS.

⁽¹³⁾	Check the daytime running light No. 2, 3 and 4 relays. See STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT.

⁽¹⁴⁾	Check the daytime running light main relay. See STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT.

⁽¹⁵⁾	Check the light control ECU (High Intensity Discharge type). Inspection information not provided by manufacturer. For location of ECU, see COMPONENT LOCATIONS .

⁽¹⁶⁾	Check the headlight control relay. See STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT.

⁽¹⁷⁾	Check the H-LP L-LWR and H-LP R-LWR fuses (15-amp). See COMPONENT LOCATIONS .

⁽¹⁸⁾	Check the headlight dimmer switch. See STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT.

⁽¹⁹⁾	Check the H-LP L-UPR and H-LP R-UPR fuses (15-amp). See COMPONENT LOCATIONS .

⁽²⁰⁾	Check the daytime running light No. 3 relay. See STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT.

⁽²¹⁾	Check ECU-B fuse (10-amp). See COMPONENT LOCATIONS .

⁽²²⁾	Check GAUGE fuse (10-amp). See COMPONENT LOCATIONS .

⁽²³⁾	Check the generator L terminal. See GENERATOR L TERMINAL CIRCUIT (W/ DRL) under CIRCUIT TESTS under BODY CONTROL SYSTEMS article under COMMUNICATION DEVICES in ACCESSORIES & EQUIPMENT.

⁽²⁴⁾	Check the parking brake switch. See INSTRUMENT PANEL article in ACCESSORIES & EQUIPMENT.

⁽²⁵⁾	Check the TAIL fuse (10-amp). See COMPONENT LOCATIONS .

⁽²⁶⁾	Check the taillight control relay. See STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT.

⁽²⁷⁾	Check the light failure relay. See appropriate INSTRUMENT PANELS article .

⁽²⁸⁾	Check the ECU-IG fuse (15-amp). See COMPONENT LOCATIONS .

⁽²⁹⁾	Check the headlight beam level control actuator. See HEADLIGHT BEAM LEVEL CONTROL ACTUATOR under COMPONENT TESTS.

⁽³⁰⁾	Check the headlight beam level control ECU. See HEADLIGHT BEAM LEVEL CONTROL ECU CIRCUIT under CIRCUIT TESTS.

⁽³¹⁾	Check the height control sensor. See HEIGHT CONTROL SENSOR (FRONT) and HEIGHT CONTROL SENSOR (REAR) under COMPONENT TESTS.

⁽³²⁾	Check the headlights.

⁽³³⁾	Check the anti-lock brake system (ABS). See ANTI-LOCK - GS300 & GS430 article in BRAKES.

⁽³⁴⁾	Check the DOME fuse (10-amp). See COMPONENT LOCATIONS .

⁽³⁵⁾	Check the rear door courtesy switch. See DOOR COURTESY SWITCH CIRCUIT (REAR) under CIRCUIT TESTS and DOOR COURTESY SWITCH (REAR) under COMPONENT TESTS.

⁽³⁶⁾	Check the ignition switch. See STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT.

⁽³⁷⁾	Check the RADIO NO. 2 fuse (15-amp). See COMPONENT LOCATIONS .

⁽³⁸⁾	Check the door unlock detection switch. See appropriate POWER DOOR LOCKS, TRUNK LID & FUEL DOOR RELEASE article under DOOR LOCKS & ANTI-THEFT SYSTEMS in ACCESSORIES & EQUIPMENT.

⁽³⁹⁾	Check the front personal light. See PERSONAL LIGHT SWITCH CIRCUIT (FRONT & REAR) under CIRCUIT TESTS and PERSONAL LIGHT SWITCH (FRONT) under COMPONENT TESTS.

⁽⁴⁰⁾	Check the rear personal light. See PERSONAL LIGHT SWITCH CIRCUIT (FRONT & REAR) under CIRCUIT TESTS and PERSONAL LIGHT SWITCH (REAR) under COMPONENT TESTS.

⁽⁴¹⁾	Check the vanity light. See VANITY LIGHT CIRCUIT under CIRCUIT TESTS and VANITY LIGHT under COMPONENT TESTS.

⁽⁴²⁾	Check the luggage compartment door courtesy switch. See LUGGAGE COMPARTMENT DOOR COURTESY SWITCH CIRCUIT under CIRCUIT TESTS and LUGGAGE COMPARTMENT DOOR COURTESY SWITCH under COMPONENT TESTS.