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Home >> Plymouth >> 1978 >> Arrow Base, Automatic Trans >> Repair and Diagnosis >> Heating, Ventilation & A/C (HVAC) >> HVAC Control Systems >> Auto. A/C Systems >> Testing >> Preliminary Procedure >> "Hi-Auto"

Preliminary Procedure: "Hi-Auto"

  1. As button is pushed, compressor should be running and system should be in A/C mode, driving to Hi blower and outside air door open to 20% outside air (above 32°F ambient temperature).
  2. Blower should be running at high speed and voltmeter should read approximately the same as supply voltage at voltage regulator.
  3. Discharge air should be coming out of A/C outlets and should be dropping towards 40°F.


Turn tester mode knob to A/C. System should change from heat mode to A/C, and blower speed should increase to high. Push "Hl-AUTO" button and note the following:

There should be an increase in discharge air velocity. There should be an increase in voltage, no change in vacuum, end little or no temperature change.

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