Air Conditioning Control Assembly: Inspection

WARNING: This page is about a different car, the 2004 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: Checking Indicator Illumination Operation (W/O Lexus Navigation System)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Using the tester as shown in Fig 2 , test the continuity.
If continuity exists, replace the heater control.

If no continuity exists, replace the bulb.

Fig 2: Checking Indicator Bulb Continuity (W/O Lexus Navigation System)
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.
INSPECT A/C CONTROL ASSEMBLY CIRCUIT (See TERMINALS OF ECU )

Fig 3: Inspecting Indicators Operation (W/O Lexus Navigation System)
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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: Inspecting Indicators Operation (W/ Lexus Navigation System)
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002