Inspection Procedure

1. Operate the rheostat and check that the quantity of light for the combination meter, audio system and A/C control panel etc. are normally changed.

1. B: CHECK AND REPLACE COMBINATION METER ASSY 
2. A: Go to next step. 

1. Measure the voltage according to the value(s) in STANDARD  .

   Standard: 

   STANDARD
   
   

   Terminal	No Condition	Specified condition
   C7-38 - Body ground	Ignition SW is ON	Below 1 V - 10 to 14 V Pulse generation (*1)

   Fig 1: Identifying Combination Meter Connector Terminal C7-38

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HINT:

Inspection using oscilloscope (*1).

HINT:

Duty ratio changes as illumination becomes darker ("A" becomes longer).

Fig 2: Waveform

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. NG: CHECK AND REPLACE COMBINATION METER ASSY 
2. OK: Go to next step. 

1. Check continuity between terminals 1 (T) and 3 (E) of light control rheostat when light control rheostat operation as shown in chart below.
   Fig 3: Switch Position Continuity Table

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   Fig 4: Identifying Light Control Rheostat Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Check light control rheostat resistance.
   1. Measure the resistance between terminals 1 (T) and 3 (E) of light control rheostat.

      Standard resistance: Approx. 10 k? 

   2. Measure the resistance between terminals 1 (T) and 2 (ILL-) of light control rheostat when operating the light control rheostat. Check that the resistance value changes continuously.

      Standard resistance: 

      STANDARD RESISTANCE
      
      

      Condition	Resistance (Ω)
      When turned brightest position	Approx. 10
      Other conditions of the above	Between change 0 - 10

1. NG: REPLACE LIGHT CONTROL RHEOSTAT 
2. OK: Go to next step. 

1. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 
2. OK: CHECK AND REPLACE COMBINATION METER ASSY