How to Fix a Stuck Relay on ac Unit

Is your air conditioner acting weird? You may have tested the circuit breaker and the thermostat, but still couldn’t troubleshoot. The main culprit can be the compressor start relay.

Our Ac units have a relay for switching high-voltage elements. In the case of AC relays, there are generally two main concerns. They can either get stuck or get damaged. If the relay contacts get stuck, the AC will not turn on or turn off according to your command. Before deciding on replacing, you may want to give it a try on fixing. But, how do you fix an air conditioner relay?

Let’s go ahead with us! We will walk you through all you need to know and answer all of your questions.

What does an AC relay switch do?

Before going ahead, you need to know what is the function of the relay in the ac. To cool your home to a specific temperature, the relay goes on and off during cooling cycles. The relay consists of a low-voltage coil and a high-voltage switch. The switch is sometimes known as “contact points”. Normally we send a low-voltage signal to energize the proper relay by turning on the thermostat.

When you turn the thermostat on cool, a 24V current flows to the compressor. This current makes the relay contacts close to providing a path for power to go to the compressor, which is the core component of the ac. So, the compressor working depends on the proper working of the ac relay.

What causes AC relay failure?

Finding out the reason behind the failure is difficult. But, several factors may be responsible.

• Faulty control switch
• Faulty computer
• Faulty pressure switch
• Low refrigerant

What are the symptoms of a bad AC relay?

Now the question is, how can you tell if a relay is bad? There are a few signs that will indicate the relay needs your attention. 

1. The ac will provide inconsistent cooling
2. If the relay is stuck, it will remain in the open state. So, when you give turn-off command, the AC will still be on. 
3. If the relay has a significant amount of damage, the ac will not turn on at all. Because the compressor will not get power. 
4. Another way to tell is shaking the relay after disconnecting it. If you find any rattling noise, that means the relay requires replacement. 

What is a stuck relay on the AC unit?

Relay switches can become jammed or damaged over time, making it impossible for the thermostat to communicate with the fan. Because there is arching in contacts when they close. This arcing generates heat which in turn causes the relay contact to stick together and weld shut in the closed position. 

This indicates the fan isn’t getting the commands you’re sending to the thermostat. As a result, even if your air conditioner is turned off, the fan will continue to operate. Now let’s move on to see how do you unstuck a relay.

How to Fix a Stuck Relay on ac Unit

If you have already found out the condition of the compressor starting relay on the ac, you may want to now fix it. Let’s go ahead and see how to do that.

1. Knock the relay several times

If there is no major issue, knock the relay a few times. This might sound funny and not effective. Trust me, it’s one of the most effective solutions. But, will tapping a relay make it work? Well, the relay is an electromechanical switch. As it has moving parts, tapping may work sometimes. Remember, it may solve the problem sometimes, not always.

2. Clean the relay

If you notice some dirt or debris is stuck on the relay, clean them. It may help to unstuck the relay. To clean it, first, find the relay switch location following the user guide. You can also search for its location on the internet with the AC model name.

3. Replace it

If nothing works, that means the relay is not usable anymore. Now you have to consider replacing it. It’s good to find a professional technician to help in this case, but you can do it on your own too. Let’s go ahead and see how you can do that.

How to Replace a damaged relay of an AC Unit?

After trying to fix the relay, if you find out the relay is completely damaged, it’s time to replace it. For replacing the ac relay by yourself, follow the steps below:

1. Find a relay that matches the older one in shape, size, and specifications.
2. Turn off the circuit breaker to disconnect the power
3. Write terminal ID on each terminal of wires to keep track
4. Pull the terminal connector using a needle nose piler
5. Unscrew the ac relay from the unit
6. Place the new relay and screw it. 
7. Finally, connect back the wires according to the masking ID.

Frequently Asked Questions (FAQs)

1. Where is the AC relay located?

Ans: You may find the relay on the sides or the back of the air conditioner unit. Manufacturers normally mount them on the firewall or the fender wall.

2. How much does it cost to replace AC relay?

Ans: When an AC relay has gone bad, it hinders the normal operation of other components. You may feel you room is hot though air conditioning is on. Replacing a relay of ac unit doesn’t cost much, it may cost around 20-100 USD.

Final Words

So far, we discussed how can you find out the issues with the ac relay and how to fix it. If the relay is only stuck, you will not need to replace it. Relays are often overlooked but can cause big troubles. So, try checking on them regularly and keep the contacts clean. It will help in the healthy and proper operation of the air conditioner. But sooner or later, it may need replacement. 

If you have tried all the methods of fixing the relay and couldn’t solve the problem, try seeking professional technicians’ help. But don’t waste time as it can harm the life of the air conditioner. Hopefully, this discussion was helpful.