I have my outdoor AC unit that I turned on after winter, but it won't turn off unless I flip the breaker. I reset it and it still stays on without responding to the thermostat. I've visually checked everything and cleaned the grill, but it seems like it's blowing slightly cooled air. I've also reset the thermostat and changed the batteries multiple times. I'm curious what else I should check before the technician arrives, considering I haven't examined the condenser or relay yet.
3 Answers
Another thing you could try is disconnecting your thermostat from the wall to check if the outside unit still runs. Sometimes, the thermostat itself can get stuck closed.
It sounds like the contactor might have failed. If you're comfortable working with electricity, you could replace it yourself; otherwise, just have the tech handle it.
Your contactor is likely stuck closed. If you flip the breaker and look for the contactor (a black plastic part with screws), you can try spraying it with WD-40 and see if that helps temporarily. It’s a cheap part to replace and not too difficult to do yourself.
Good question! It can get stuck due to dirt or wear and tear. A new one should last better, but keeping it clean helps prevent future issues.

Okay sounds great. Something I can do for sure. I'm going to replace it no matter what then, but if it's 'stuck closed,' why can't it be opened to repair it?