Inspection Procedure

1. Remove the A/C amplifier with connectors still connected.
2. Turn ignition switch ON.
3. Change the set temperature to activate the air mix damper and measure the voltage between terminals TPP and SG-4 of A/C amplifier.

   Voltage: 

   MAX. COOL: 3.5 to 4.5 V 

   MAX. HOT: 0.5 to 1.8 V 

HINT: As the set temperature increases, the voltage decreases gradually without interruption.

Fig 1: Identifying TPP & SG-4 Terminals

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Fig 2: Identifying Inspection Chart

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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. 

1. Remove the air mix damper servo sub-assy.
2. Measure resistance between terminals 1 and 2 of air mix damper servo sub-assy connector.

   Resistance: 4.2 to 7.8 kΩ 

3. While operating air mix damper servo sub-assy as shown in the procedure on PRE-CHECK  , measure resistance between terminals 1 and 3 of air mix damper servo sub-assy.

   Resistance: 

   MAX. COOL: 3.4 to 6.2 kΩ 

   MAX. HOT: 0.8 to 1.6 kΩ 

HINT: As the air mix damper servo sub-assy moves from cool side to warm side, the resistance decreases gradually without interruption.

Fig 3: Measuring Resistance Between Terminals 1 And 2 Of Air Mix Damper Servo Sub-Assy Connector

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Fig 4: Identifying Position Of Air Mix Damper Servo

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Fig 5: Identifying Graphic Of Resistance (Air Mix Damper Servo)

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NG: REPLACE AIRMIX DAMPER SERVO SUB-ASSY 

OK: Go to next step. 

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: CHECK AND REPLACE HEATER CONTROL HOUSING SUB-ASSY