Inspection Procedure

1. PREPARATION: 
   1. Remove A/C control assembly with connectors still connected AIR CONDITIONING .
   2. Turn Ignition Switch To On.

1. Check: 
2. Measure voltage between terminals TW and SG of A/C control assembly connector at each engine coolant temperature.

1. OK: 
   1. Voltage 
   2. At 0°C (32°F): 2.8-3.2V 
   3. At 40°C (104°F): 1.8-2.2 V 
   4. At 70°C (158°F): 0.9-1.3 V 

Hint:

As The temperature increases, the voltage decreases.

1. NG: Go To Step 2 
2. OK: Proceed to next circuit inspection shown on problem symptoms table, see  PROBLEM SYMPTOMS TABLE  . However, If DTC 14 is displayed, check and replace A/C control assembly. 

Fig 1: Checking TW & SG Terminal Voltage

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 2: Checking Engine Coolant Temperature Sensor
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. PREPARATION: 
2. Remove engine coolant temperature sensor AIR CONDITIONING .

1. CHECK: 
2. Measure resistance between terminals 1 and 3 of engine coolant temperature sensor connector at each temperature.

1. OK: 
   1. Resistance: 
   2. At 0°C (32°F): Below 50 k/ohms 
   3. At 40°C (104°F): 2.5-2.7 k/ohms 
   4. At 100°C (212°F): Over 0.3 k/ohms 

Hint:

As The Temperature Increases, The Resistance Decreases Gradually.

1. NG: Replace engine coolant temperature sensor. 
2. OK: Go to next step 

1. NG: Repair or replace harness or connector. 
2. OK: Check and replace A/C control assembly.