Air Conditioning Control Assembly: Inspection

WARNING: This page is about a different car, the 2003 Lexus LX 470. However, it is still accessible from the selected car via links, so may be relevant.

w/o LEXUS navigation system: INSPECT ILLUMINATION OPERATION
1. Connect the positive (+) lead from the battery to terminal C10 and negative (-) lead to terminal C19 then check that the indicators' illuminate.
  If operation is not as specified, check the faulty bulb.
2. Remove the bulb. (See DISASSEMBLY )
  
  Fig 1: Inspecting Illumination Operation
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Using the tester as shown in the illustration, test the continuity.
  If continuity exists, replace the heater control.
  
  If no continuity exists, replace the bulb.
  
  Fig 2: Testing Continuity
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
w/o LEXUS navigation system: INSPECT INDICATORS OPERATION
1. Connect the positive (+) lead from the battery to terminal C22 and negative (-) lead to terminal C12.
2. Check that the indicators come on while operate the switches.
  If operation is not as specified, replace the heater control.
  
  Fig 3: Inspecting Indicators Operation
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
INSPECT A/C CONTROL ASSEMBLY CIRCUIT (See TERMINALS OF ECU )
w/LEXUS navigation system: INSPECT INDICATORS OPERATION
1. Connect the positive (+) lead from the battery to terminal A8 and negative (-) lead to terminal A16.
2. Check that the indicators come on while operating the switches.
  If operation is not as specified, replace the heater control.
INSPECT A/C CONTROL ASSEMBLY CIRCUIT (See TERMINALS OF ECU )

Fig 4: Inspect Indicators Operation
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002