Fixing a Stuck AC Relay Switch: How Pros Do It

ac relay switch

Is your air conditioner refusing to turn on or making unusual clicking noises? Your device might have a stuck AC relay switch.

As the top-rated air conditioner repair experts in Denver, JC Mechanical offers prompt, friendly, and quality service no matter your air conditioner problem. Because we know enduring high heat without a working air conditioner poses a risk to your safety, we’re available for 24-hour help.

Don’t waste time looking around for a better option because you won’t find one. If you think you have a stuck relay switch, give us a call, and we’ll find a solution.

What Is a Relay Switch?

The relay switch is the small electrical component within the air conditioner that regulates the flow of electricity. When you turn on the device, the relay switch opens, allowing electricity to power the air conditioner. When the air conditioner reaches your set temperature, the relay switch closes and cuts off power.

The relay switch helps modern air conditioners run with a high level of energy efficiency, but sometimes they become stuck. The switch is usually located near the back of the air conditioner, close to the compressor and the control panel. You can identify the switch by the three wires protruding from it: an input wire, a ground wire, and a power feed wire.

The life expectancy of a relay switch isn’t measured in years. Rather, the switch should last for about 50,000 cycles. One cycle is the process of your air conditioner turning on, cooling the air, and then turning off.

Because your relay switch activates every time your device turns on or off, the more frequently it cycles, the faster your switch ages. A normal cycle lasts between 15 and 20 minutes.

Signs Your Relay Switch Needs Repairs

When a relay switch becomes stuck in the open or closed position, you’ll notice any of the following signs:

  • If your air conditioner doesn’t turn on, it’s likely your relay switch can’t open.
  • Sometimes, the air conditioner turns on but then shuts off for no reason, regardless of the ambient temperature.
  • When you hear strange clicking noises coming from your air conditioner, it could be the relay switch sticking.
  • If you examine the relay switch and notice damage, corrosion, or debris, the switch needs cleaning or replacement and is more likely to stick.

How To Prevent Damage to Your Relay Switch

You can help your relay switch last longer by practicing the following good habits.

Moderate Your Usage

Because air conditioners are so integral to staying comfortable during the hot summer months, many homeowners don’t hesitate to run their devices constantly. However, not only does this cost you significant money, it wears out your air conditioner more quickly, often causing the relay switch to stick.

To help limit how often you use your air conditioner, use the following techniques:

  • Use an efficient setting: The Department of Energy suggests setting your thermostat to 78 degrees to run it most efficiently. This saves you money on your energy bills and extends the life of your air conditioner. 
  • Fans: Ceiling fans are the most effective way of cooling your home, besides an air conditioner. Used correctly, a ceiling fan makes the ambient temperature in your home feel four to seven degrees cooler. This means you can set your thermostat higher without sacrificing comfort.
  • Use your windows: On temperate days, open your windows to create a nice breeze and utilize your body’s natural ability for evaporative cooling. On hotter days, close your blinds to block out the sun, which most experts agree can reduce your heat gain by up to 45%. Upgrade to high-quality blinds like solar shades to increase your home’s energy efficiency.
  • Improve insulation: High-quality insulation prevents air from leaking through your walls, doors, and windows and improves your energy efficiency. With good insulation, you can run your air conditioner less frequently without any reduction in comfort.
  • Turn it off: Turn off your air conditioner when you’re not home, as cooling air you’re not using is a waste of energy and money and puts an unneeded burden on your air conditioner. Make a point of getting outside or leaving your house for a public place with excellent air conditioning. Not only will this save you money on your energy bills, but using your air conditioner less means it lasts much longer.

Perform Regular Cleaning

To help avoid corrosion and dust buildup, regularly clean the outdoor portion of your air conditioner. Use a hose with a gentle stream to spray off any accumulating dirt without damaging the device. You should clean your air conditioner at least once a year, usually during maintenance, but if you live in an area with heavy pollution, you should clean it more often.

Change the Air Filter

If your air filter clogs, the dirt and dust it would normally filter out accumulate on your air conditioner and its components. Change your air filter every 30 days to avoid further damage and serious complications. If you smoke, own pets, have respiratory issues or allergies, or live in an area with heavy pollution, check your air filter more frequently.

Schedule Annual Maintenance

To keep your air conditioner in peak working order, schedule regular maintenance. The best time is during the spring to help prepare your air conditioner for heavy usage during the summer. Some homeowners schedule a second checkup during the fall to determine how much wear and tear their device experienced during the hot season.

How the Pros Fix a Relay Switch

Never attempt to fix the AC relay switch by yourself. Air conditioners are fragile pieces of equipment, and one mistake can cause serious damage to your device. Before your HVAC technician works on your air conditioner, they will shut off its power supply to avoid receiving an electrical shock.

1. Clean the Relay Switch

To adequately clean the relay switch, the technician first removes it from the air conditioner. Using a rag and either alcohol or vinegar, we’ll clean the wires where they connect with the rest of the device. We then rinse the connections with water and ensure they’ve dried completely. 

If the problem with the relay switch was simply that it had accumulated too much dust, this should fix the issue.

2. Inspect the Switch for Damage

After cleaning the relay switch, we’ll closely inspect it for damage to determine whether it needs replacing. If we see no damage, we’ll put the switch back into the air conditioner to determine whether we solved the problem. If we notice damage, we’ll need to replace the switch.

3. Replace the Relay Switch

To replace the relay switch, we must confirm we have the right type for your specific air conditioner. We keep an ample stock, but occasionally we must order the piece. We then remove your old switch and replace it with the new one.

The new switch should last for the remaining life of your air conditioner.

Contact JC Mechanical for All Your Air Conditioner Needs

Are you convinced your AC relay switch is stuck and needs an inspection? Instead of risking greater damage or the safety hazards inherent with DIY AC repair, reach out to JC Mechanical. We offer a wide range of services including:

  • Air conditioner maintenance, repair, and installation
  • Thermostat repair and installation
  • Furnace and boiler repair and installation
  • Comprehensive water heater service
  • Full service for heat pumps
  • Indoor air quality improvement, including ductwork repair, humidifier installation, UV light installation

To book an appointment, call us at 720-807-8953.

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