Inspection Procedure

CHECK ILLUMINATION
1. Operate the rheostat and check that the luminosity for the audio system and A/C control panel is normally changed.
  
  Fig 1: Audio System And A/C Control Panel Illumination Check Reference Table
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. B: Go to step 4 .
2. A: Go to step 2 .
CHECK LIGHT CONTROL RHEOSTAT
1. Check continuity between terminal 1 and 2 of light control rheostat when light control rheostat operation is as shown in the Fig 2.
  
  Fig 2: Light Control Rheostat Continuity Reference Table
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Check light control rheostat resistance.
1. Measure the resistance between terminal 1 and 3 of light control rheostat.
  Standard resistance:
  
  Approx. 10 km%ohm
2. Measure the resistance between terminal 1 and 4 of light control rheostat while operating the light control rheostat. Check that the resistance value changes continuously.
  Standard resistance:
  
  When turned fully clockwise: Approx. 10 km%ohm
  
  When turned fully counterclockwise: Approx. 0 km%ohm
  
  Fig 3: Identifying Light Control Rheostat Connector Terminals
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG: REPLACE LIGHT CONTROL RHEOSTAT
2. OK: GO TO STEP 3 .
CHECK HARNESS AND CONNECTOR (BETWEEN LIGHT CONTROL RHEOSTAT AND DRIVER SIDE J/B ECU)
1. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
2. OK: CHECK AND REPLACE DRIVER SIDE JUNCTION BLOCK
INSPECT COMBINATION METER ASSY (ILL-)
(REFERENCE) INSPECTION USING OSCILLOSCOPE
1. Check the output wave.
1. Remove the combination meter with connectors still connected.
2. Connect the oscilloscope to the terminal ILL- of combination meter and body ground.
3. Turn the ignition switch ON.
4. Check the signal waveform.
  
  Fig 4: Identifying Combination Meter Connector ILL - Terminal
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 5: Oscilloscope And Vehicle Condition Reference Table
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 6: Identifying Oscilloscope Waveform
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG: REPAIR OR REPLACE HARNESS AND CONNECTOR
2. OK: GO TO STEP 5 .
CHECK HARNESS AND CONNECTOR (BETWEEN DRIVER SIDE J/B ECU AND COMBINATION METER ASSY)
1. NG: CHECK AND REPLACE COMBINATION METER ASSY
2. OK: CHECK AND REPLACE DRIVER SIDE JUNCTION BLOCK