Page 345 of 4500
Fig. 110: Checking Harness And Connector (Cool Air Bypass Servomotor - Air Conditioning 
Amplifier) 
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC. 
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR  
OK: REPLACE AIR CONDITIONING AMPLIFIER (SEE REPLACEMENT
 )  
CIRCUIT DESCRIPTION 
The air inlet servomotor is controlled by the A/C amplifier and moves the air inlet servomotor to the desired 
position. 
Fig. 111: DTC Detection Item Trouble Area Chart
 
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC. 
WIRING DIAGRAM  
         
        
        
     
        
        Page 351 of 4500
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: REPLACE AIR CONDITIONING AMPLIFIER (SEE REPLACEMENT )  
CIRCUIT DESCRIPTION 
In this circuit, the compressor assembly receives a signal on refrigerant compression required by the air 
conditioning amplifier. Based on the signal, the compressor assembly changes the degree of refrigerant 
compression. 
Fig. 116: DTC Detection Item Trouble Area Chart
 
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC. 
WIRING DIAGRAM 
Fig. 117: Compressor Solenoid Circuit
  
         
        
        
     
        
        Page 356 of 4500
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR  
OK: REPLACE AIR CONDITIONING AMPLIFIER (SEE REPLACEMENT
 )  
CIRCUIT DESCRIPTION 
This sensor detects the exhaust gas (NOx) outside the vehicle and sends a signal to the A/C amplifier. 
Fig. 121: DTC Detection Item Trouble Area Chart
 
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC. 
WIRING DIAGRAM  
         
        
        
     
        
        Page 363 of 4500
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: REPLACE AIR CONDITIONING AMPLIFIER (SEE REPLACEMENT )  
CIRCUIT DESCRIPTION 
The cool air bypass damper control servomotor is controlled by the A/C amplifier and moves the cool air bypass 
damper to the desired position. 
WIRING DIAGRAM 
Fig. 126: Cool Air Bypass Damper Control Servomotor Circuit (Driver Side)
 
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC. 
INSPECTION PROCEDURE  
         
        
        
     
        
        Page 368 of 4500
Amplifier) 
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC. 
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR  
OK: REPLACE AIR CONDITIONING AMPLIFIER (SEE REPLACEMENT
 )  
CIRCUIT DESCRIPTION 
The cool air bypass servomotor is controlled by the A/C amplifier and moves the cool air bypass damper to the 
desired position. 
WIRING DIAGRAM  
         
        
        
     
        
        Page 373 of 4500
Amplifier) 
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC. 
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR  
OK: REPLACE AIR CONDITIONING AMPLIFIER (SEE REPLACEMENT
 )  
CIRCUIT DESCRIPTION 
This circuit controls the amount of the coolant flowing to the heater core by a signal from the A/C amplifier, 
and adjusts the temperature at the air outlets. 
WIRING DIAGRAM 
Fig. 132: Water Valve Control Servomotor Circuit
 
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC. 
         
        
        
     
        
        Page 378 of 4500
Amplifier) 
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC. 
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR  
OK: REPLACE AIR CONDITIONING AMPLIFIER (SEE REPLACEMENT
 )  
CIRCUIT DESCRIPTION 
This circuit turns the servomotor and changes each damper position by receiving the signals from the A/C 
amplifier assy. When the AUTO switch is on, the A/C amplifier changes the mode between "FACE", "BI-
LEVEL" and "FOOT" following the temperature setting. 
WIRING DIAGRAM  
         
        
        
     
        
        Page 388 of 4500
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
OK: REPLACE AIR CONDITIONING AMPLIFIER (SEE REPLACEMENT
 )  
CIRCUIT DESCRIPTION 
This servomotor is controlled by the A/C amplifier. Air flow temperature changes when moving the air mix 
damper to the target point. The target point can be detected with the air mix damper position sensor. 
WIRING DIAGRAM