2005 Lexus LS 430FACTORY OEM SERVICE PROCEDURE

Problem Symptoms Table

PROBLEM SYMPTOMS TABLE - WINDOW DEFOGGER SYSTEM

Symptom Suspected Area
Rear window defogger does not operate (Indicator ON)
  1. DEFOG H-fuse
  2. FRIG fuse
  3. DEFOG relay
  4. Rear window defogger wire
  5. Wire harness
Rear window defogger does not operate (Indicator OFF)
  1. DEFOG H-fuse
  2. FRIG fuse
  3. DEFOG relay
  4. Heater control panel assy (w/o LEXUS navigation)
  5. Multi-display assy (w/LEXUS navigation)
  6. Rear window defogger wire
  7. Wire harness
Mirror heater does not operate (Indicator ON)
  1. D DOOR fuse
  2. P DOOR fuse
  3. D-IG1 relay
  4. Outer rear view mirror assy
  5. Wire harness
Mirror heater does not operate (Indicator OFF)
  1. D DOOR fuse
  2. P DOOR fuse
  3. D-IG1 relay
  4. Heater control panel assy (w/o LEXUS navigation)
  5. Multi-display assy (w/LEXUS navigation)
  6. Outer rear view mirror assy
  7. Wire harness

HINT:

The wind defogger system is part of the large-scale multiplex communication system. This system features shared communication wiring that reduces the wiring complexity of the communication lines. The first step in any repair is to confirm the proper operation of the communication system. Proceed with troubleshooting after the communication has been verified (see MULTIPLEX COMMUNICATION SYSTEM ).

Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.

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