Air Conditioner Relay is basically a switch. It is a low-voltage-operated switch used to turn high voltage heavy-duty AC components. The AC wall thermostat circuit and switches are not capable of handling these high voltage components without Air Conditioning Relay.
Using a Digital MultiMeter (DMM) device, there should be zero resistance across the power and the relay points.
This means that the relay is failing. You may use an electrical contractor lubricant spray to smear the relay for short-term repair, though replacement of the relay is highly recommended.
When your AC relay never remains open even when energized or it remains closed when power is turned off, it must be replaced.
Note that replacement relays must match the original's function, voltage and amperage. To know more about which Air Conditioner Relay fit your unit best, do not hesitate to contact us.