I. The outdoor heat-exchanger fan. i. The outdoor heat-exchanger fan runs at a low speed (with a

Question

i. The outdoor heat-exchanger fan runs at a low speed (with a humming noise), when the home temperature is below the set-point. ii. When home temp. in high, fan runs at full speed, like normal.iii. When A/C breaker is shutoff (in main switchboard), the fan stops.Need help diagnose the problem.