“A bad contactor” is one of the most common A/C repairs. But what is a contactor, and what causes it to malfunction?
We get this question, “What’s a contactor?” from many customers, because it is one of the components that breaks the most often!
Does that mean that contactors are poorly made? Absolutely not! But it is a problem that’s easy to fix, and today we want to explain that in more detail.
What is a contactor?
This is the part of your A/C that controls how much electricity flows in. So if your A/C is turned off, the contactor is up. And when the A/C is turned on, the contactor is down, letting electricity through.
More specifically, the A/C contactor sends electricity to the condenser and the fan components, in order to power them. The contactor has terminals on it that electricity runs through.
As you can imagine, if this important piece of machinery controlling electricity is broken, then your A/C will go down! But there’s more than one possible problem an A/C contactor can have.
The first problem is a “pitted” contactor. As you can imagine, this means that there are little pits on the surface of the contactor. No matter how careful you are, and no matter what brand of A/C you have, eventually the effects of electricity and heat damage will make pits in the electrical terminals of the contactor.
The contactor can no longer create contact between your thermostat and your condenser.
The other common issue that happens with an A/C contactor is that it gets an electrical fault, which has the same result:
The thermostat clicks on, but electricity can’t pass from the thermostat to the contactor to the condenser.
How do you know if you have a bad A/C contactor?
It’s a little difficult for anyone who’s not trained in the field to know whether their A/C issue is with the contactor or another component, but there are a few signs that point to contactor problems …
- You hear a humming coming from the A/C, but it isn’t actually turning on.
- You hear a clicking or chattering noise, indicating that the contactor terminals are dirty.
- Your A/C unit never shuts off. That would mean that part of the contactor has melted due to electricity and heat, and then your A/C can’t shut off because it can’t block and control the flow of electricity. In that case, you would want to call us right away!
It is possible to test whether your A/C contactor is working using a multimeter, and connecting it to the contactor terminals … But if you’re not completely sure how to do that, we recommend calling one of our techs instead!