RV Air Conditioner Repair: What's Wrong and How to Fix It
Quick Answer
Most RV AC failures are caused by a blown capacitor (the cylindrical component that stores electrical charge), which is a $50–$100 part and a 15-minute technician swap. Next is fan motor failure (no spinning fan, no cooling) and refrigerant leaks. Before calling for service, confirm your AC is getting 120V power and the thermostat is set to Cool mode.
Your RV air conditioner was running fine, and suddenly it stops cooling or won't turn on. AC systems are less complex than many RV appliances, but failures are common in the harsh environment of an RV (heat, vibration, road salt). The #1 reason RV ACs fail is a blown capacitor—a cheap, quick fix. The #2 reason is fan motor failure; #3 is refrigerant loss from a slow leak. This guide walks you through diagnosis, tells you what you can safely test yourself, and shows you when professional service is essential. Most RV AC repairs run $200–$600, but a capacitor replacement can be as cheap as $100.
Capacitor Failure (Most Common RV AC Problem)
The capacitor is a cylindrical electrical component (usually about 3 inches tall, found near the compressor) that stores electrical energy needed to start the AC compressor motor. When a capacitor fails (typically after 5–10 years), it can't provide enough energy to start the compressor. You'll hear the AC unit try to start but fail, making a clicking or buzzing sound repeatedly. Sometimes the fan runs but the compressor won't kick in, so you get no cooling. A failed capacitor is diagnosed by visually inspecting it—if it's swollen, bulging, leaking dark fluid, or has a burnt smell, it's definitely failed. Even if it looks normal externally, a multimeter test can confirm it (a technician can test capacitor microfarads). Capacitor replacement is simple and cheap ($50–$150 part, $100–$200 labor). Most RV technicians or even handy DIYers can replace it in 15 minutes—it's just unplugging the old one and snapping in a new one. The capacitor must match the original in microfarads (uF), so bring the old one to the RV parts store or snap a photo of the label. Capacitors fail frequently in RVs because of heat exposure and vibration. If you've replaced one, keeping a spare on hand is smart maintenance.
Fan Motor Failure (No Cooling Despite Power)
The AC fan motor pulls air over the cold evaporator coils and pushes cool air into your RV. If the fan motor dies, the AC unit might still run (you hear the compressor), but no cool air flows into the cabin. You'll feel warm or room-temperature air coming from the AC vents. A dead fan motor is diagnosed by looking at the fan behind the AC cover—it should be spinning when the AC is on. If it's not moving or barely creeping, the motor is failing. A seized or slow fan motor is caused by worn bearings, debris jamming the blades, or electrical failure of the motor windings. Temporary fix: clear any debris from the fan blades and try rotating the fan by hand (turn off power first)—if it won't budge, the motor is seized. Fan motor replacement costs $200–$400 including labor. The motor must match your AC model exactly. If the motor is seized, order a new one from your AC manufacturer (Coleman, Dometic, Atwood are common RV brands). Installation involves unbolting the old motor and bolting in the new one, then checking that the fan spins freely.
Compressor Failure or Overheating
The compressor is the heart of the AC system, pressurizing refrigerant to create the cooling cycle. If the compressor has failed or is overheating, the AC won't cool even if the fan is running. Compressor failure is diagnosed by a technician checking compressor pressure with gauges (you can't safely test this yourself). If pressure is zero or extremely low, the compressor is dead or severely damaged. Compressor failure is usually caused by a refrigerant leak (see below), years of hard use, or contamination inside the system from a previous leak. A failed compressor must be replaced ($400–$800 part, plus $300–$500 labor). Replacement involves evacuating the old refrigerant, removing the compressor, flushing the lines, and installing a new compressor with new refrigerant. This is a technician-only job—refrigerant handling requires EPA certification. Compressor overheating is less common but can happen if the condenser is severely clogged with dust (preventing heat dissipation). If your AC runs but cuts out after 30–60 minutes, the compressor might be overheating and a thermal cutoff is protecting it. Clean the condenser coils (compressed air from outside) and try again.
Refrigerant Leak (Slow or Fast)
Refrigerant is the substance that actually absorbs heat and provides cooling. If a refrigerant line is cracked or a connection is loose, refrigerant slowly leaks out. Eventually, there's not enough refrigerant to cool effectively. A slow leak manifests as gradually declining cooling efficiency (works great the first year, noticeably weaker year two, barely works by year three). A fast leak (a severed line or large crack) causes rapid cooling loss over days or weeks. A refrigerant leak is diagnosed by a technician using a refrigerant detector (a small handheld device that senses escaping refrigerant). If a leak is found, the location and severity determine repair approach: (1) a loose connection just needs tightening ($0 fix), (2) a small pinhole leak can be sealed with UV-cure epoxy ($100–$200), or (3) a large crack requires replacement of the entire line or coil ($300–$600). Once the leak is fixed, the system must be evacuated and recharged with new refrigerant—another $200–$400. A refrigerant recharge alone doesn't fix a leak; it's only a temporary solution. Address the leak first, then recharge. Always use a certified technician for refrigerant work; the substance is controlled and can't be vented to the atmosphere.
Control Board or Thermostat Failure
The AC control board (or thermostat) receives your temperature setting and turns the compressor and fan on/off. If the board is dead or the thermostat is broken, the AC won't respond to your commands. You'll turn on the AC, set the temperature, but nothing happens—no fan, no compressor, no error, just silence. A control board failure can happen due to power surges, moisture intrusion, or years of heat exposure. Diagnosis requires a multimeter test of the power supply and relay circuits; a technician can determine if the issue is a loose connection, a failed relay, or a completely dead board. Replacement options range from $150–$400 depending on whether it's a simple relay board or the entire control module. For some RVs, replacing the thermostat (simpler component) solves the problem; for others, the main circuit board is faulty and must be replaced. A power reset (turn off breaker for 5 minutes) sometimes wakes up a stuck board, but if that doesn't work, professional diagnosis is needed.
Evaporator Coil Iced Over or Clogged
The evaporator coil is where cold happens—refrigerant inside the coil absorbs heat, and air blown over it cools your RV. If the coil gets clogged with dust or ice forms on it (due to excessive moisture), cooling is blocked. You'll feel weak or no cold air from the vents despite the AC running. A clogged coil is usually caused by a dirty air filter (replace it monthly) or very humid conditions. Ice on the coil happens when humidity is high and the coil gets too cold. Temporary fix: increase the thermostat setting a few degrees to prevent ice formation, and replace your air filter immediately. If ice is visible around the AC unit, turn off the AC and let it melt (2–4 hours), then replace the filter and restart. If the coil is clogged with permanent debris (not ice), a technician must clean it—this involves accessing the coil and using compressed air or liquid cleaner. Coil cleaning typically costs $150–$300. If clogging is severe, the coil must be replaced ($400–$600). The best prevention is monthly air filter replacement and avoiding running the AC in very high humidity without opening windows or running a fan.
When to Call a Pro
Call a technician if the capacitor is swollen or obviously failed, if the compressor won't start or is overheating, if a refrigerant leak is suspected, if the control board is dead, if the fan motor is seized, or if you see ice on the evaporator coil. Compressor work, refrigerant handling, and electrical diagnostics require professional certification and specialized equipment.
Frequently Asked Questions
Can I replace an RV AC capacitor myself?
Yes, if you're comfortable with electrical work. A capacitor is just unplugged and replugged; the challenge is getting the old one out and matching the new one to the original specs (microfarads rating). Take a photo of the label, buy an identical capacitor at an RV parts store, and swap it. However, if you're uncomfortable working with electrical components, have a technician do it ($100–$200 total cost is reasonable).
How often should I replace my RV AC air filter?
Replace your AC air filter monthly during heavy use, or at least every 3 months. A clogged filter reduces cooling efficiency, strains the fan motor, and can cause evaporator coil icing. Replacing filters is the cheapest maintenance you can do ($5–$15 per filter) and prevents expensive repairs down the line.
What refrigerant should I use if my RV AC needs recharging?
You must use the exact refrigerant type specified for your AC model—usually R-410A, R-22, or R-134a. Check your AC label or manual. Never mix refrigerant types. Recharging requires EPA-certified technician; you can't DIY this legally. Always fix any leaks first before recharging, or you'll waste refrigerant money.
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Last updated: 2026-02-18