AC unit humming when I turn off the system.
I have a Dometic brand AC unit with a analog thermostat. When I turn the thermostat to off there is a humming noise coming from the AC unit on the roof. The only way it stops is to flip the breaker. T...
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The relay should be a replaceable part. BUT
I'd go with DrewE's recommendation first; disconnect the existing thermostat and simulate a new one, touching the control wires to ground. You won't get a shock, it's very low voltage.
Specifically touch high fan wire to ground, and then without disconnecting, add the cool wire also to ground. let it run for a few min, and then disconnect all the wires. listen to see if the compressor stops. If it does, great, just need a new thermo. If not, bummer, probably need a new relay.
I'd go with DrewE's recommendation first; disconnect the existing thermostat and simulate a new one, touching the control wires to ground. You won't get a shock, it's very low voltage.
Specifically touch high fan wire to ground, and then without disconnecting, add the cool wire also to ground. let it run for a few min, and then disconnect all the wires. listen to see if the compressor stops. If it does, great, just need a new thermo. If not, bummer, probably need a new relay.
