LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 2003 >> LS 430 >> Repair and Diagnosis >> External Pages >> Different car >> Section 387 (Air Conditioning System) >> Heater Control Assembly >> Heater Control Assembly Inspection
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Heater Control Assembly Inspection

WARNING: This page is about a different car, the 2002 Toyota Prius. However, it is still accessible from the selected car via links, so may be relevant.
  1. Inspect illumination operation  :
    1. Connect the positive (+) lead from the battery to terminal 5 and negative (-) lead to terminal 10, then check that the illumination lights up.

      If operation is not as specified, check the faulty bulb.

      Fig 1: Locating Center Cluster Module Terminals 5 & 10
      G01065499Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Apply the tester as shown in Fig 2 to the test for continuity.
      Fig 2: Center Single Bulb For Continuity
      G01065500Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      If continuity exists, replace the heater control.

      If no continuity exists, replace the bulb.

  2. Inspect indicator operation  :

    Connect the positive (+) lead from the battery to terminal 1 and negative (-) lead to terminal 7, then check that the illumination light up.

    Fig 3: Testing Indicator Light Operation
    G01065501Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    If operation is not as specified, proceed next inspection.

  3. Inspect F/R indicator operation  :

    Connect the positive (+) lead from the two 1.5 V dry cell batteries to terminal 1 and negative (-) lead to terminal 3, then check that the F/R indicator lights up.

    Fig 4: Testing Fresh Air/Recirculated Air Indicator Light
    G01065502Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    If operation is as specified, replace the A/C amplifier.

    If operation is not as specified, replace the cluster module circuit.

  4. Inspect A/C indicator operation  :

    Connect the positive (+) lead from the two 1.5 V dry cell batteries to terminals 1 and negative (-) lead to terminal 5, then check that the A/C indicator lights up.

    Fig 5: Testing A/C Indicator Light
    G01065503Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    If operation is as specified, replace the A/C amplifier.

    If operation is not as specified, replace the cluster module circuit.

  5. Inspect MAX. A/C indicator operation  .

    Connect the positive (+) lead from the two 1.5 V dry cell batteries to terminal 1 and negative (-) lead to terminal 15, then check that the MAX. A/C indicator lights up.

    Fig 6: Testing Max Indicator Light
    G01065504Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    If operation is as specified, replace the A/C amplifier.

    If operation is not as specified, replace the cluster module circuit.

  6. Inspect switch continuity  .

    Check the continuity between terminals while switch is pressed, as shown in Fig 8.

    Fig 7: Testing Fresh Air/Recirculated Air, A/C & Max Switches
    G01065506Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    Fig 8: Switch Specifications Chart
    G01065505Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    If operation is not as specified, replace the cluster module circuit.

  7. Inspect mode control dial operation  :
    1. Check that the resistance between terminals 12 and 13 is approximately 3.0 kΩ.
    2. Connect the positive (+) lead from the three 1.5 V dry cell batteries to terminal 9 and negative (-) lead to terminal 13.
    3. Connect the positive (+) lead from the tester to terminal 12 and negative (-) lead to terminal 13, then check that the voltage at each dial position, as shown in the chart below.
      Fig 9: Testing Mode Control Dial
      G01065507Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      Fig 10: Mode Control Dial Selection Specifications
      G01065508Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    If operation is not as specified, replace the cluster module circuit.

  8. Inspect temperature control dial operation  :
    1. Check that the resistance between terminals 11 and 13 is approximately 3.0 kΩ.
      2. Fig 11: Testing Temperature Control Dial
      G01065509Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Connect the positive (+) lead from the three 1.5 V dry cell batteries to terminal 9 and negative (-) lead to terminal 13.
    3. Connect the positive (+) lead from the tester to terminal 11 and negative (-) lead to terminal 13.
    4. Gradually turn the dial from "MAX. COOL" side to "MAX. WARM" side and check that the voltage increase from 4.5 to 0.4 V.

      If operation is not as specified, replace the cluster module circuit.

  9. Inspect blower speed control dial operation  :
    1. Check that the resistance between terminals 10 and 13 is approximately 3.0 kΩ.
      2. Fig 12: Testing Blower Speed Control
      G01065510Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Connect the positive (+) lead from the three 1.5 V dry cell batteries to terminal 9 and negative (-) lead to terminal 13.
    3. Connect the positive (+) lead from the tester to terminal 10 and negative (-) lead to terminal 13 then check that the voltage at each dial position, as shown in the chart below.
      Fig 13: Blower Speed Control Specifications
      G01065511Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      If operation is not as specified, replace the cluster module circuit.

scientia non olet · About LEMON Manuals