When should I replace my AC fuse?

Author: Henry Dooley III  |  Last update: Tuesday, May 6, 2025

Blowing the fuse cuts the power to the unit to prevent electrical damage. If your AC has shut down and won't start again, especially if you've noticed odd electrical behavior immediately before the shutdown, chances are the fuse has done its job and will need to be replaced.

How long do AC fuses last?

This could be because of too-high levels of refrigerant in the AC, or as a result of frequently turning the machine off and then back on very quickly (within a minute of turning it off). The lifespan of a fuse can be up to 20 years.

How do you know if your AC fuse is bad?

If you think your air conditioner has blown a fuse, the first sign you'll notice is that the outside AC unit is inoperable. The best way to check for a blown fuse is by using a voltmeter. Be warned — you are working with live electricity and should use extreme caution when troubleshooting your system.

When to replace an AC fuse?

Here are a few signs to watch out for that indicate a potentially blown fuse:
  1. No response from the AC unit: If your AC does not turn on when you set it to cool, this could indicate a blown fuse.
  2. Tripped circuit breaker: A blown fuse may cause the circuit breaker to trip, cutting power to the AC system.

How do you know when a fuse needs replacing?

An electrician knows it's time to replace a fuse or circuit breaker when it's no longer functioning as it should. For fuses, if they blow, it's a clear sign they need to be replaced. This happens when the fuse detects an overload or short circuit, and its metal strip melts to stop the flow of electricity.

How To Replace a Fuse on a Furnace or AC Air Handler Control Board

Do I need an electrician to change a fuse?

Replacing a blown fuse is a simple DIY repair that costs little to perform. However, if your home blows fuses often, it may indicate that your fuse box needs upgrading to a circuit breaker panel, perhaps with higher amperage available. Only a local electrician should replace a fuse box with circuit breakers.

What are the symptoms of a blown fuse?

Common Signs of a Blown Fuse
  • Electrical Components Not Working: If your car's radio, power windows, or headlights suddenly stop functioning, a blown fuse might be the culprit.
  • Dim or Flickering Lights: Dimming or flickering lights can indicate an overloaded electrical circuit leading to a blown fuse.

How much does it cost to replace an AC fuse?

AC Fuse, Circuit Breaker, or Relay Replacement Cost

Expect to pay between $15 and $300 to have AC fuse and circuit breaker issues addressed or relays in your AC unit replaced. These projects do not usually take more than a couple of hours.

Can a bad AC fuse cause AC not to work?

Without the fuse, your air conditioner could be damaged by the current and you could end up needing to replace the whole unit. Because the fuse has blown, the air conditioner is protected. If your AC fuse is blown, it's most likely that your air conditioner will stop functioning entirely.

Why is my AC unit not kicking on?

Check the thermostat

You should check if it's been set to the correct temperature and also make sure it's set to “cool”. If the AC settings are not right, it won't turn on. You can also check if the batteries in the thermostat are fresh and replace them if needed.

Will the AC unit run if fuse is blown?

If the fuse is blown, the air conditioner will quit working and you'll need to have your AC repaired.

How do I know if my AC breaker is bad?

How to Tell if a Circuit Breaker Is Bad
  1. It's Frequently Tripping.
  2. You Notice Visible Damage.
  3. It Won't Stay Reset.
  4. It's Hot to Touch.
  5. You Notice a Burning Smell.
  6. You Experienced a Recent Electrical Surge.
  7. Your Breaker Is Old and Worn Out.
  8. You Have an Overloaded Circuit.

How do I reset my AC fuse?

If you have fuses, you can only reset the AC by taking the fuse out. After the 30 minutes lapses, reinstall the fuse back in position if it's still in good condition, but replace a worn-out fuse with a new one. Now turn the AC back on, confirm if the thermostat is set to cool, and observe how the unit functions.

How do I tell if my AC fuse is blown?

In addition to a sudden stop, these signs of blown AC fuses require your attention:
  1. Strange sounds are coming from your air conditioning unit.
  2. Your circuit breaker keeps tripping.
  3. Your unit smells like it is burning or gives off the smell of exhaust.
  4. Water is leaking from the unit.

How often do fuses need to be replaced?

There's debate on exactly how long fuses last, with some manufacturers claiming fuses can last, 20, 30, even 40 years. However, in the auto industry it's recommended to check or consider replacing fuses after 10.

Can an AC breaker go bad?

With general wear and tear, breakers can go bad over time, too. You'll know your circuit breaker is bad if you notice these signs: Circuit breaker is hot to the touch. Burning odor around the breaker.

Can a blown fuse stop AC from blowing cold air?

It may sound ridiculous, but if your AC is not blowing air, make sure you plug the cord in correctly and that there is no damage to the cable or plug head. If they are both fine, it could be an issue with the electrical panel itself. A tripped breaker or blown fuse could be the cause of it not working.

Why isn't my AC compressor turning on?

You'll want to have the unit examined for signs of a blown fuse, tripped circuit breaker, broken thermostat, or dirty air filters. Dirty or clogged filters commonly make AC compressors stop working. When it comes to operating your cooling system properly, be realistic with the temperature setting on your thermostat.

How to know if a fuse is blown?

If it looks broken or cracked, it is likely blown. Additionally, some blown fuses have metallic residue running throughout the glass container. Inspect each and every fuse in the box to get a sense of how many are blown and which parts of the home are impacted.

How much is labor for AC replacement?

HVAC Pro Cost

You'll want to ensure a crucial task like this is done correctly. To avoid potential injuries or problems with unit sizing or installation, ask an experienced local AC installation pro for a quote for your system. Most people pay $500 to $2,500 in labor for AC replacement.

Does O'Reilly check fuses?

Oreillys or any auto parts store should be able to help you out.

Can I replace a fuse myself?

Replacing a fuse is a relatively easy, do-it-yourself home task that you can tackle with a little information and some electrical home safety savvy. If your home has a fuse box, the best advice is to plan ahead and become familiar with the electrical panel and with the types of fuses it requires.

Can a fuse be bad but still work?

It depends. If the fuse is for a system unrelated to the ignition, starter, or battery, your car will likely start and run. Is it bad to drive with a blown fuse? It might be.

Where is the fuse in my AC?

Fuse Box Location: Your AC unit's fuse box is typically located near the outdoor condenser unit. Look for a labeled disconnect box or electrical panel. Fuse Type: There are two main types of fuses – cartridge and glass tube. Both should have a visible filament inside.

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