8 Common RV Air Conditioner Problems & What to Do About Them

Reliable air conditioning is one of the most important components of any RV comfort system, especially when you're traveling in warm weather. But like any appliance, even a high-quality RV air conditioner can experience performance issues over time. Whether you're in the middle of a cross-country trip or preparing for your next weekend getaway, knowing how to spot and fix common problems with RV air conditioners can help you stay cool and avoid costly repairs or downtime.

This guide covers the most frequent RV AC issues, what causes them, and how to fix or prevent them. We also offer maintenance tips and when it might be time to replace your unit. Whenever you need help with common RV air conditioner problems, you can count on Lippert to provide you with high-quality solutions!

1. RV Air Conditioner Not Cooling Properly
2. AC Not Turning On at All
3. RV AC Blowing Warm Air
4. Air Conditioner Short Cycling
5. Musty or Bad Odors When AC Runs
6. Loud or Unusual Noises
7. Ice Build-Up on the AC Unit
8. Thermostat Issues
9. Regular Maintenance Tips to Prevent AC Problems
10. When to Repair vs. Replace Your RV Air Conditioner

Symptoms: The unit powers on and air is flowing, but the air coming out isn't as cold as it should be.

Possible Causes:

• Dirty air filters or coils that restrict airflow
• Undervoltage from your power source
• A malfunctioning thermostat
• A refrigerant leak (rare but possible)

What to Do: Start by cleaning or replacing the AC’s air filters, which can accumulate dust quickly and block airflow. If the filters are clean and the problem persists, inspect the evaporator and condenser coils for dirt or debris. Make sure your RV is receiving proper voltage — low campground power can impact AC performance. If your thermostat seems off, recalibrate it or consider upgrading to a Furrion digital thermostat for more accurate temperature control.

Symptoms: The unit is completely unresponsive, with no fan or cooling function.

Possible Causes:

• Tripped breaker or blown fuse
• Faulty control board
• Loose or disconnected wiring

What to Do: Check the breaker panel in your RV and reset any tripped breakers. If that doesn’t work, inspect the wiring at both the thermostat and the rooftop unit for visible issues. The control board — essentially the “brain” of the AC system — may need replacement. Lippert carries OEM replacement parts that ensure compatibility and performance.

Symptoms: The AC runs, but only warm air blows out of the vents.

Possible Causes:

• Frozen evaporator coils due to restricted airflow

• Dirty condenser fins

• A malfunctioning compressor

What to Do: Turn off the AC and allow the unit to defrost fully. Then, clean the coils and condenser fins carefully using an AC-safe coil cleaner. If the compressor isn't engaging or making unusual noises, it may need professional inspection or replacement. Persistent problems with cooling could mean it's time for a new, energy-efficient model like the Furrion Chill Cube.

Symptoms: The AC repeatedly turns on and off in short bursts, never running long enough to cool the RV.

Possible Causes:

• Poor thermostat placement (near a window or heat source)
• Faulty capacitor or control board
• Oversized AC for the RV size

What to Do: First, check the thermostat’s location. It may be registering inaccurate temps. If that's not the issue, inspect the capacitor, which helps start the compressor and fan. A soft start kit can help manage start-up current draw and reduce stress on the system. If the unit is oversized, consider switching to a more appropriately sized model.

Symptoms: A musty, mildew-like smell fills the RV whenever the air conditioner is on.

Possible Causes:

• Mold or mildew buildup in the AC unit
• Clogged or dirty condensate drain pan

What to Do: Remove the AC shroud and inspect the evaporator coil and fan blades for visible mold or grime. Use a non-toxic AC coil cleaner and allow everything to dry thoroughly. Ensure the drain pan is clear and properly sloped so that moisture doesn’t pool inside the unit. Regular cleaning can prevent odors and keep the air quality high.

Symptoms: Grinding, buzzing, clicking, or rattling sounds when the unit is running.

Possible Causes:

• Loose components
• Worn-out fan motor
• Foreign objects or debris in the unit

What to Do: Safely remove the AC shroud and inspect for any visible loose screws or debris. Tighten any components that may have loosened during travel. If the motor is the source of the noise, consider replacing it with a Lippert OEM fan motor designed to match your AC system. Regular inspections can help you catch small issues before they lead to major repairs.

Symptoms: Ice forms on the evaporator coils or even drips from the AC vents.

Possible Causes:

• Restricted airflow from clogged filters
• Low ambient temperatures
• Low refrigerant levels

What to Do: Turn off the AC and allow it to thaw completely. Check and clean your filters and ensure nothing is blocking return airflow. Avoid using the AC in very cold temperatures where condensation can freeze. If the issue persists despite good airflow, a technician should check refrigerant levels.

Symptoms: Inaccurate temperature readings, lagging response, or unresponsive interface.

Possible Causes:

• Faulty temperature sensor
• Loose wiring
• Dead batteries (for battery-powered models)

What to Do: Reset the thermostat and inspect for wiring issues. If the thermostat is several years old or no longer functions reliably, upgrade to a Furrion digital thermostat, which offers improved accuracy, touch controls, and compatibility with Furrion Chill rooftop units.

Regular RV AC maintenance is essential to keeping your RV air conditioner running smoothly and avoiding common problems. One of the most important tasks is cleaning the air filters. During peak travel seasons, filters can collect dust and debris quickly, restricting airflow and forcing the system to work harder than necessary. Aim to clean or replace them at least once a month when the AC is in frequent use.

Before powering on your air conditioner, especially at campgrounds or unfamiliar locations, it's important to verify that your RV is receiving adequate voltage. Low or fluctuating power can strain your system and lead to long-term damage. Using a surge protector is a smart way to protect your AC unit and other electronics from sudden power spikes.

Another key maintenance point is inspecting the rooftop seals around the AC unit. These seals can deteriorate over time, and if left unchecked, may allow water to leak into your RV. Periodic inspections and resealing as needed can help prevent this issue. You should also keep an eye on the condensate drain line, which removes moisture from the system. If the line becomes clogged, it can lead to internal moisture buildup and promote mold growth.

Finally, scheduling an annual inspection with a certified RV technician is a proactive way to ensure your AC unit is operating efficiently. A technician can check the electrical system, refrigerant levels, and overall condition of your unit, catching small issues before they develop into costly repairs.

Deciding whether to repair or replace your RV air conditioner often comes down to the age of the unit, the nature of the problem, and the cost of the fix. In many cases, replacing worn components or performing basic maintenance can restore proper function. However, some issues, like a failed compressor, are much more expensive to address and may not be worth the investment in an older unit.

If repair costs begin to approach half the price of a new AC system, it's usually a smart financial decision to opt for a replacement. This is especially true if your current unit is more than eight to ten years old. Over time, even well-maintained systems lose efficiency and become more prone to breakdowns, particularly under heavy use or in extreme conditions.

Another consideration is performance. If your air conditioner is struggling to keep your RV cool, runs constantly without making a difference, or causes other electrical issues, upgrading to a more efficient and properly sized model could make a significant difference in comfort and energy consumption. Modern systems like the Furrion Chill Cube offer better cooling power, quieter operation, and improved reliability, making them a worthwhile investment for regular travelers.

Ultimately, whether you choose to repair or replace, Lippert has the OEM replacement parts, expert resources, and upgraded AC solutions to support you every step of the way.

No RV air conditioner is completely immune to wear and tear, but many problems can be addressed with basic maintenance and troubleshooting. By staying ahead of common issues and keeping your unit clean and well-serviced, you can ensure cool, comfortable travel all season long.

If you’re experiencing any of these problems, Lippert has the OEM replacement parts, support resources, and upgraded Furrion AC units to help you fix it fast or upgrade with confidence.

Explore our full collection of RV AC parts and accessories today or contact our support team to get expert help.