Inspection Procedure

WARNING: This page is about a different car, the 2004 Lexus ES 330. However, it is still accessible from the selected car via links, so may be relevant.

INSPECT HEATER CONTROL HOUSING SUB-ASSY(TPO, SG1)
1. Remove the A/C amplifier with connectors still connected.
2. Turn ignition switch ON.
3. Measure voltage between terminals TPO and SG-1 of A/C amplifier.
  Voltage:
  
  FACE: 3.5 to 4.5 V
  
  DEF: 0.5 to 1.5 V
HINT: As the mode damper servo sub-assy is moved from FACE side to DEF side, the voltage decreases gradually with out interruption.

Fig 1: Measuring Voltage Between Terminals TPO And SG-1 Of A/C Amplifier
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 2: Inspection Procedure Chart
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

B: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE (SEE PROBLEM SYMPTOMS TABLE )

C: CHECK AND REPLACE HEATER CONTROL HOUSING SUB-ASSY

A: Go to next step.
INSPECT MODE DAMPER SERVO SUB-ASSY
1. Remove the mode damper servo sub-assy.
2. Measure resistance between terminals 1 and 2 of mode damper servo sub-assy connector.
  Resistance: 4.2 to 7.8 kΩ
3. While operating mode damper servo sub-assy as in the procedure on PRE-CHECK , measure resistance between terminal 1 and 3 of mode damper servo sub-assy.
  Resistance:
  
  DEF: 3.4 to 6.2 kΩ
  
  FACE: 0.8 to 1.6 kΩ
HINT: As the mode damper servo sub-assy moved from DEF side to FACE side, the resistance decreases gradually with out interruption.

Fig 3: Measuring Resistance Between Terminals 1 And 2 Of Mode Damper Servo Sub-Assy Connector
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 4: Identifying Position Of Damper Servo Sub-Assy
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 5: Identifying Graphic Of Resistance
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: REPLACE MODE DAMPER SERVO SUB-ASSY

OK: Go to next step.
CHECK HARNESS AND CONNECTOR(BETWEEN AIR OUTLET DAMPER POSITION SENSOR AND HEATER CONTROL HOUSING SUB-ASSY)
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: CHECK AND REPLACE HEATER CONTROL HOUSING SUB-ASSY