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Home >> Lexus >> 2004 >> LX 470 >> Repair and Diagnosis >> Electrical >> Motors, Switches, Relays >> Body Electrical (Troubleshooting) >> Problem Symptoms Table >> Headlight And Taillight System:

Headlight And Taillight System:

This system uses the body control system, so check the body control system before you proceed with troubleshooting (See HOW TO PROCEED WITH TROUBLESHOOTING ).

HEADLIGHT AND TAILLIGHT SYSTEM SPECIFICATION

Symptom Suspect Area Action
"Automatic light control system" does not operate.
  1. Automatic Light Control Sensor
  2. Light Control Switch
  3. Door Courtesy Switch
  4. Wire Harness
  5. Body ECU (Main)
  1. INSPECTION
  2. INSPECTION
  3. INSPECTION
  4. -
  5. HOW TO PROCEED WITH TROUBLESHOOTING
Auto turn-off system does not operate when the driver's door is opened.
  1. Drivers Door Courtesy Switch
  1. INSPECTION
Auto turn-off system:
Headlight and taillight do not come on.
  1. Wire Harness
  2. Body ECU (Main)
  1. -
  2. HOW TO PROCEED WITH TROUBLESHOOTING
Auto turn-off system:
Headlight and taillight stay on.
  1. Wire Harness
  2. Body ECU (Main)
  1. -
  2. HOW TO PROCEED WITH TROUBLESHOOTING
Only one headlight comes on.
  1. Bulb
  2. Daytime Running Light No. 3, 4 Relays
  3. Wire Harness
  4. Body ECU (Main)
  1. -
  2. INSPECTION
  3. -
  4. INSPECTION
"LO-beam" does not come on (All).
  1. Engine Room J/B Relay Circuit
  2. Wire Harness
  3. Body ECU (Main)
  1. INSPECTION
  2. -
  3. INSPECTION
"LO-beam" does not come on (One side).
  1. Bulb
  2. H-LP L-LWR Fuse
  3. H-LP R-LWR Fuse
  4. Wire Harness
  1. -
  2. -
  3. -
  4. -
"HI-beam" does not come on (All).
  1. Headlight Dimmer Switch
  2. Wire Harness
  3. Body ECU (Main)
  1. INSPECTION
  2. -
  3. INSPECTION
"Hl-beam" does not come on (One side).
  1. Bulb
  2. H-LP L-UPR Fuse
  3. H-LP R-UPR Fuse
  4. Daytime Running Light No.3 Relay
  5. Wire Harness
  1. -
  2. -
  3. -
  4. INSPECTION
  5. -
"Flash" does not come on.
  1. Headlight Dimmer Switch
  2. Wire Harness
  3. Body ECU (Main)
  1. INSPECTION
  2. -
  3. INSPECTION
Headlight does not come on.
  1. Bulb
  2. Headlight Dimmer Switch
  3. Light Control Switch
  4. Daytime Running Light No.3, 4 Relays
  5. Engine Room J/B Relay Circuit
  6. Wire Harness
  7. Body ECU (Main)
  1. -
  2. INSPECTION
  3. INSPECTION
  4. INSPECTION
  5. INSPECTION
  6. -
  7. HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE
Headlight does not come on with light control switch in HEAD.
  1. Light Control Switch
  2. Wire Harness
  3. Body ECU (Main)
  1. INSPECTION
  2. -
  3. HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE
Headlight does not go off with light control switch in OFF.
  1. Engine Room J/B Relay Circuit
  2. Wire Harness
  3. Body ECU (Main)
  1. LOCATION
  2. -
  3. HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE
Headlight flickers.
  1. Bulb
  2. Wire Harness
  1. -
  2. -
Headlight is dark.
  1. Bulb
  2. Wire Harness
  1. -
  2. -
Taillight does not come on with light control switch in TAIL.
  1. Light Control Switch
  2. Engine Room J/B Relay Circuit
  3. Wire Harness
  4. Body ECU (Sub)
  5. Body ECU (Main)
  1. INSPECTION
  2. INSPECTION
  3. -
  4. HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE
  5. HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE
Taillight does not go off with light control switch in OFF.
  1. Light Control Switch
  2. Engine Room J/B Relay Circuit
  3. Wire Harness
  4. Body ECU (Sub)
  5. Body ECU (Main)
  1. INSPECTION
  2. INSPECTION
  3. -
  4. HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE
  5. HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE
Headlight does not come on with engine running and light control switch in OFF.
  1. ECU-B2 Fuse
  2. ECU-IG1 Fuse
  3. Daytime Running Light No.3, 4 Relays
  4. Generator L Terminal
  5. Parking Brake Switch
  6. Wire Harness
  7. Body ECU (Main)
  1. -
  2. -
  3. INSPECTION
  4. GENERATOR
  5. INSPECTION
  6. -
  7. HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE
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