Smoke or burning smell coming from window air conditioner: What it means and how to fix it

Few things are more startling than seeing smoke or smelling a burning odor from your window air conditioner. This is a clear sign of a serious problem that requires immediate attention to prevent potential fire hazards or damage to the unit.

But we have good news: There are some common troubleshooting steps you can take to diagnose and resolve the issue without a service technician.

Let’s dive in so you can find out what’s going wrong in your air conditioning unit.

If you find out that you need any replacement parts for your air conditioner while you’re troubleshooting, you can enter your model number at AppliancePartsPros.com to order them. Most orders arrive in just two business days, and we have thousands of free guides to show you how to install your new parts.

Important: The troubleshooting information provided in this article may not apply to your specific appliance model. While we strive to offer helpful advice for DIY appliance repairs, variations in models and configurations can lead to differences in troubleshooting steps, error codes and part replacements. For the most accurate guidance, we strongly recommend consulting the technical sheet for your specific appliance model.

Safety precautions

When working on any appliance, remember to keep safety first. Here are some tips to keep in mind:

• Always power off and unplug your appliance or switch off the circuit breaker before you attempt any maintenance or replacement work. This keeps you safe by eliminating any risk of electric shock.
• If the appliance has recently been used, give it plenty of time to cool down before working on it.
• Take your time while working to prevent accidents and personal injuries. Rushing is the enemy of precision.
• Work in a well-lit area so you can see and access appliance parts.
• Keep your workspace free of clutter and other obstacles. Keep children and pets away from the work area.
• Never work on internal parts with wet hands. Make sure the work area is completely dry.
• Check the user manual to see if there are specific installation or safety instructions related to your appliance or replacement part.
• Be gentle when handling or removing parts. Excessive force might damage the appliance or cause personal injury.
• Wear insulated work gloves to protect your hands from sharp metal parts and debris.
• When working with wires, avoid touching any exposed wires or terminals. If you need to touch a wire, use a non-conductive tool or wear insulating gloves to prevent electrical shock.
• Always take photos or make a note of wiring terminals or other connections before disconnecting them to make reassembly easier.
• Don’t test live voltage with a multimeter if you’re unfamiliar with how to prevent short-circuiting.

Read more: How to Clean Your Air Conditioner the Easy Way  

How to troubleshoot your air conditioner

Find out why your window AC is smoking or releasing a burning smell by following these steps.

Step 1: Check the fan motor

1. Unplug the air conditioner from the power source.
2. Remove the front panel to access the internal parts.
3. Find the fan motor, which is typically behind the front grille or in the back portion of the unit.
4. Visually inspect the fan motor for any signs of damage, such as cracks, breaks, or excessive wear on the bearings.
5. Make sure the fan blade is securely attached to the motor shaft and can rotate freely without any obstructions.
6. Set a multimeter to resistance mode (Ω) and use the probes to test the fan motor’s windings. The resistance should match the specifications provided in the model’s technical sheet. If the reading is significantly different, the fan motor may need to be replaced.

Step 2: Check the electrical wiring & power cord

• Inspect all visible wiring for any signs of damage, such as fraying, cracks, or burns.
• Check the condition of the power cord to make sure it’s not damaged or pinched.
• Inspect all wire connections, terminals, and electrical components for any loose or unsecured connections. Tighten any loose connections and make sure they’re making proper contact.
• Check for any wiring that’s touching bare metal, which can create a short.
• Check the circuit breaker or fuse that the air conditioner is connected to. Make sure the air conditioner is the only appliance on the circuit and that it’s not exceeding the circuit’s amperage rating.

If you find any damage to the wiring or power cord, replace them as needed.

Step 3: Check airflow

• Inspect the air intake and exhaust vents for any blockages that could be restricting airflow.
• Clean or replace the air filters if they’re clogged with dirt and debris.
• Make sure the condenser coils are clean and not blocked by any debris. You can use a condenser cleaning brush or vacuum to remove dust, dirt, pet fur, hair and other debris from the coils.
• Check that the air conditioner is installed in a location with adequate clearance around the unit. Remove any furniture, curtains, or other items that may be blocking airflow around the unit.

Step 4: Check the insulation

Check the condition of the insulation on the refrigerant lines, compressor, and other internal parts. Look for any signs of deterioration, cracks, or crumbling of the insulation material.

Replace any damaged or worn insulation.

Step 5: Check the outdoor condenser coils

Look over the outdoor condenser coils for signs of dirt, debris, or damage. Use a soft-bristle brush or a garden hose (with low water pressure) to carefully clean the condenser coils. Be careful not to bend or damage the delicate fins.

Replace the condenser coils if needed.

Read more:   How to get better air quality from your window air conditioner

More information

Thank you for reading! We hope this guide helped you get your window air conditioner working again.

If you have any other appliance repair needs or projects, don’t hesitate to explore our other troubleshooting guides and videos.

If you need replacement parts or some extra help with ordering them, grab your model number and head over to AppliancePartsPros.com, where you can chat with a pro, read our DIY blog and more.

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