Inspection Procedure

CHECK ILLUMINATION

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

ILLUMINATION CHECK

A	All light do not change.
B	Combination meter does not change.

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

CHECK COMBINATION METER ASSY
1. Remove the combination meter assy with connectors still connected.
2. Turn the ignition switch to ON.
3. Measure the voltage between terminals C8-1 and C8-19 of combination meter assy connector.
  Standard voltage: 0.1 - 4.1 V
  
  Fig 1: Identifying Combination Meter Assy Connector Terminals C8-1 And C8-19
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG: CHECK AND REPLACE COMBINATION METER ASSY
2. OK: Go to next step.

INSPECT LIGHT CONTROL RHEOSTAT

Check continuity between terminals 1 (TC) and 3 (T) of light control rheostat when light control rheostat operation as shown in chart below.

LIGHT CONTROL RHEOSTAT TERMINALS CONTINUITY

Switch position	Terminal (Symbol)	Continuity
Most brighten position	1 (TC) <==> 3 (T)	No continuity
Except most brighten position	1 (TC) <==> 3 (T)	Continuity

Check light control rheostat resistance.

Measure the resistance between terminals 1 (TC) and 3 (T) of light control rheostat.
Standard resistance: Approx. 10 kΩ

Measure the resistance between terminals 1 (TC) and 4 (RV) of light control rheostat when operating the light control rheostat. Check that the resistance value changes continuously.

Standard resistance:

LIGHT CONTROL RHEOSTAT TERMINALS RESISTANCE

Condition	Resistance (kΩ)
When turned brightest position	Approx. 10
Other cnditions of the above	Change between 0 - 10

Fig 2: Identifying Light Control Rheostat Terminals 1 (TC), 3 (T) And 4 (RV)

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

CHECK HARNESS AND CONNECTOR
1. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
2. OK: CHECK AND REPLACE MULTIPLEX NETWORK BODY ECU