My inside unit works on cool, the squirrel cage comes on automatically. It also comes on when I turn it to fan on the thermostat. On heat it's not working. The unit is humming and you can feel heat coming from the coil area. I can hear the thermostat send the signal telling it to turn on the heat but the fan won't work.
When you say the unit is humming, do you mean the fan motor itself is humming? If the fan motor is humming then the problem is with the fan motor but if it isn’t it’s with the indoor fan relay which has two lines coming out of it. One for cooling and ventilation and the other for heating. If the contacts for the line for the heating are bad then you need to replace the relay.
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