Heater Control Assembly (Manual A/C): Inspection

Inspect Illumination Operation
Connect the positive (+) lead from the battery to terminal 15 and negative (-) lead to terminal 16 then check that the illuminations lights up.

Fig 1: Inspecting Illumination Operation
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If operation is not as specified, check the faulty bulb.
Inspect Bulb
Apply the tester as shown in the illustration to the test for continuity.

Fig 2: Inspecting Bulb
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If continuity exists, replace the heater control.

If no continuity exists, replace the bulb.
Inspect RECIRC Indicator Operation
1. Connect the positive (+) lead from the battery to terminal 2 and the negative (-) lead to terminal 7,25.
  
  Fig 3: Inspecting RECIRC Indicator Operation
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2. Push the REC button in and then check that the indicator lights up.
If operation is not as specified, replace the switch circuit board.
Inspect Dimming Operation
1. Connect the positive (+) lead from the battery to terminal 2 and the negative (-) lead to terminal 7, 25 while press the switch.
  
  Fig 4: Inspecting Dimming Operation
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2. Push the REC button in and then check that the indicator lights up.
3. Connect the positive (+) lead from the battery to terminal 15 and then check that the indicator dims.
If operation is not as specified, replace the switch circuit board.
Inspect A/C Indicator Operation
1. Connect the positive (+) lead from the battery to terminal 2 and negative (-) lead to terminal 10,25.
  
  Fig 5: Inspecting A/C Indicator Operation
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2. Push the A/C button in and then check that the indicator lights up.
If operation is not as specified, replace the switch circuit board.
Inspect Dimming Operation
1. Connect the positive (+) lead from the battery to terminal 2 and negative (-) lead to terminal 10,25 while press the switch.
  
  Fig 6: Inspecting Dimming Operation
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2. Push the A/C button in and then check that the indicator lights up.
3. Connect the positive (+) lead from the battery to terminal 20 and then check that the indicator dims.
If operation is not as specified, replace the switch circuit board.
Inspect Switch Continuity
Check the continuity between terminals while switch is pressed, as shown in Fig 7.

Fig 7: Displaying Switch Connection Based On Conditions
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Fig 8: Inspecting Switch Continuity
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Inspect Temperature Control Switch Operation
1. Check that the resistance between terminals 11 and 13 is approx. 3.0 k Ohms.
  
  Fig 9: Inspecting Temperature Control Switch Operation
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2. Connect the positive (+) lead from the three 1.5 V dry cell batteries to terminal 11 and negative (-) lead to terminal 13.
3. Connect the positive (+) lead from the tester to terminal 12 and negative (-) lead to terminal 13.
4. Gradually turn the switch from "MAX. WARM" side to "MAX. COOL" side and check that the voltage increase from 0 to 4.5 V
If operation is not as specified, replace the heater control base.
Inspect Blower Speed Control Switch Operation
Check the continuity between terminals at each switch position as shown in Fig 10.

Fig 10: Displaying Switch Connection Based On Conditions
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If continuity is not as specified, replace the heater control base.

Fig 11: Inspecting Blower Speed Control Switch Operation
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Inspect Mode Switch Continuity
Check the continuity between terminals at each switch position as shown in Fig 12.

Fig 12: Displaying Switch Connection Based On Conditions
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If continuity is not as specified, replace the switch.

Fig 13: Inspecting Mode Switch Continuity
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