Mazda MX-3 silhouetteMX-3

Air Conditioner — On-vehicle Inspection: Thermoswitch / Evaporator

G-69prose procedure

On-vehicle Inspection

Thermoswitch

Thermoswitch — On-vehicle Inspection

  1. 1
    Remove the glove compartment and glove compartment cover.
  2. 2
    Run the engine at idle.
  3. 3
    Turn the A/C switch off and set the fan switch off to the fourth position to operate the blower fan for a few minutes.
    Illustration of the A/C control panel showing the row of mode/function pushbuttons (including the A/C button at the right), the temperature/recirculation slider levers, and the fan-speed slider with positions marked OFF, 1, 2, 3, 4.
  4. 4
    After a few minutes, turn the fan switch off and stop the engine.
    The thermoswitch contacts will be open if the evaporator temperature is below 0.4 ± 0.7 °C {32.5 ± 1.0 °F}
  5. 5
    Disconnect the thermoswitch connector and check for continuity between the switch terminals.
    Interior view of the dashboard/instrument-panel area with a tester (multimeter) connected; a magnified circular inset shows the thermoswitch connector with terminals labelled A and B.
  6. 6
    If there is no continuity, replace the thermoswitch. (Refer to page G-68.)

Inspection

Thermoswitch

Thermoswitch — Bench Inspection

  1. 1
    Immerse the sensing bulb in a container of ice water.
    Bench inspection: the thermoswitch sensing bulb immersed in a container of ice water with a tester (analog ohmmeter) connected to terminals A and B to check continuity.
  2. 2
    Check for continuity between the switch terminals.

Thermoswitch Continuity

Above 5°C
ContinuityYes
Below 0°C
ContinuityNo
3. If not as specified, replace the thermoswitch. (Refer to page G-68.)

Evaporator

Evaporator — Inspection

  1. 1
    Check the evaporator fins for blockage. If the fins are clogged, clean them with compressed air.
    Illustration of the evaporator core (cooling unit) showing the finned coil and the inlet/outlet pipe fittings, used to inspect fins for blockage and fittings for cracks/damage.
  2. 2
    Check the fittings for cracks and other damage. Replace the evaporator if necessary. (Refer to page G-68.)
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See also

page G-68

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