Practice question

A driver complains the bus A/C blows warm only at idle but cools at higher engine speed. The most likely cause is:

  1. A failed blend door
  2. A plugged cabin filter
  3. A normal feature
  4. Low charge or weak condenser airflow at idle (e.g., failed electric fan or low charge)

Answer: D — Low charge or weak condenser airflow at idle (e.g., failed electric fan or low charge)

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Practice more: ASE S7 Air Conditioning Systems & Controls (School Bus) Practice Questions - ASE S7 - Air Conditioning Systems & Controls (School Bus) Certification Exam →