RV Air Conditioner: Repair It or Replace It?

Most RV air conditioners that quit have a failed part that costs under $100, usually the capacitor. By Agile RV Housing's figures, a typical repair runs $25 to $100 in parts, while a full replacement typically runs about $1,800 installed. Run the checks below in order and you will know which one you are facing before you spend anything.

What does RV AC repair or replacement cost?

A capacitor costs $25 to $39 for a Coleman Mach and $50 to $100 for a Dometic. A thermostat or control board is about $100. A mobile tech charges a $150 service call plus $150 per hour. A new rooftop unit is $1,200 to $1,400, or about $1,800 installed. Those are Agile RV Housing's figures, checked against public prices below.

The table scrolls sideways on a phone.

The Agile RV Housing figures come from Agile RV Housing's repair records across more than 100 RV housing placements nationwide. Public prices checked September 2026. Retail prices change, so open the source link before you buy.

Is my RV air conditioner actually dead?

Probably not. A rooftop unit has one expensive part, the compressor and the sealed refrigerant loop around it. Everything else that stops it from cooling is a part that costs less than a tech's service call. Run these eight checks in order, simplest first, and stop at the first one that explains what you are seeing.

1. Power supply and breaker. Nothing happens at all, no fan and no hum, or the breaker trips the moment the unit tries to start. This points to power not reaching the unit: a tripped breaker in the RV panel or at the pedestal, a bad shore cord or adapter, a generator that is not putting out power, or an inverter that is not sized to run an air conditioner. If the fan runs but the compressor hums and gives up, check the voltage at an interior outlet with a plug-in meter while the unit tries to start. A long extension cord, a weak campground pedestal, or a small generator will sag under the compressor's starting load. Typical cost to fix: nothing, or a heavier cord.
2. Thermostat settings and wiring. The fan runs but the compressor never starts, or nothing responds at all, or the unit never shuts off. Check that the mode is set to cool and not fan only, that the set point is below the room temperature, and that a wall thermostat has fresh batteries if it uses them. Both Coleman Mach and Dometic wall thermostats run on 12 volt power from the RV's house battery, so a dead battery or a blown 12 volt fuse can stop a unit that has perfect shore power. Look for a loose thermostat wire at the ceiling assembly. Typical cost to fix: nothing, or about $100 for a thermostat.
3. Dirty filter and coils. Airflow at the vents is weak, the air is only slightly cool, and the unit runs all day without catching up. Pull the return air grille and wash or replace the filter. If the evaporator coil behind it is matted with dust and pet hair, clean it with coil cleaner and a soft brush. On the roof, the condenser coil at the back of the unit collects road grime and cottonwood fluff and cannot shed heat. Our guide to an RV air conditioner that runs but does not cool walks through the cleaning in detail. Typical cost to fix: a can of coil cleaner.
4. Frozen evaporator. The unit cools well at first, then after it has run a while the airflow drops to a trickle, and you can see ice behind the return grille or water dripping as it thaws. Ice comes from low airflow across the coil: a dirty filter, the fan on low speed, or a set point far too low in humid weather. Shut the compressor off, run the fan until the ice is gone, and fix the airflow. If it keeps freezing with a clean filter, high fan speed, and a sensible set point, the refrigerant charge is low, and that means a leak in the sealed system. Typical cost to fix: nothing if it is airflow, a replacement unit if it is the charge.
5. Capacitor. The compressor hums for a few seconds and clicks off, tries to start and gives up, or starts only sometimes. The fan will not turn on its own but spins if you give it a push. The breaker trips when the compressor tries to start even though the voltage is fine. The capacitor's top is bulged or there is oil on the case. This is the most common hard part failure on a rooftop unit, and the test and swap are covered step by step below. Typical cost to fix: $25 to $39 on a Coleman Mach, $50 to $100 on a Dometic.
6. Fan motor. The fan does not turn even with a capacitor that tests good, the motor is hot to the touch and smells burnt, it squeals or grinds, or it turns much slower than it used to. Because one motor drives both the indoor blower and the outdoor condenser fan on most rooftop units, a failing motor also causes freeze ups and high head pressure that shuts the compressor down. Public prices for the part are in the table above. Replacing a motor means pulling the fan wheel and blade, which is beyond most owners, so plan on a tech for this one.
7. Control board. The thermostat calls for cooling, the capacitor and motor test good, the voltage is good, and the board still never sends power to the compressor or the fan. You may hear relays clicking with nothing happening, see the unit behave differently every time you start it, or find a wall thermostat display that stays dark even with 12 volt power present. On Dometic units the board is in the box on the ceiling assembly or on the roof. On Coleman Mach units with a wall thermostat, it is in the control box on the ceiling assembly. Typical cost to fix: about $100 for the board.
8. Compressor. With good voltage, a capacitor that tests within its rating, a running fan, and clean coils, the compressor hums and shuts off on its internal overload again and again, or it runs but the air at the vent never gets colder than the room. The first is a seized or shorted compressor. The second is a compressor that has lost its refrigerant. Neither is repaired on a rooftop unit, and this is the only item on the list that means replacement. Typical cost: $1,200 to $1,400 for a new unit, about $1,800 installed.

Notice where the compressor sits. It is last, and it is the only failure that ends in a new unit. If someone tells you the unit is dead before checking the voltage and the capacitor, ask them to check.

How do I test and replace an RV AC capacitor?

Cut all power, get on the roof, remove the shroud, discharge the capacitor, photograph the wiring, test the capacitor with a multimeter on its capacitance setting, and replace it with one that has the same microfarad rating and an equal or higher voltage rating. The steps below cover Coleman Mach and Dometic units, and the differences are small.

Before you touch anything

Before any work, disconnect shore power at the pedestal, turn off the generator, turn off the inverter, and switch off the air conditioner breaker in the RV's panel. All four. An inverter can put 120 volt power on the air conditioner circuit with the shore cord unplugged, and a generator on auto start can fire up while you are on the roof. Then set the thermostat to cool and confirm the unit stays silent.

Capacitors hold a charge after the power is off, and a charged capacitor can give you a serious shock. HVAC PRO Sales describes the safe way to discharge one: connect a resistor of 10,000 to 20,000 ohms, rated at least 5 watts, across the terminals with insulated clip leads and hold it there for 30 seconds to a minute, then confirm with a multimeter set to volts that the terminals read zero (HVAC PRO Sales). Discharge tools built for this are sold at any HVAC supply house. Shorting the terminals with a bare screwdriver also works, but it makes a large spark that can pit the terminals and damage the capacitor, so use the resistor.

Roof safety

A fall from an RV roof is the most likely way this job hurts you. Use a ladder rated for your weight, have someone hold it, and never work on a wet roof. Not every RV roof will hold a person. What carries your weight up there is the rafters, not the skin over them. Dometic's own installation manual requires roof construction with rafters or support frames on a minimum of 16 inch centers to carry a rooftop air conditioner (Dometic installation manual). Sixteen inches is a lot of unsupported decking to put a knee through, so step over the rafters rather than between them. Pop-up campers and soft-sided sections cannot take any weight at all. A factory roof ladder is the usual clue that a roof was built to be walked on, and RVBlogger uses the same rule of thumb (RVBlogger). A clue is not a guarantee. If your owner's manual does not say your roof is walkable, ask the manufacturer, spread your weight over a sheet of plywood, or hand the job to a tech.

Where the capacitors are

On both brands the capacitors live on the roof under the plastic shroud, inside a metal electrical box on the side of the unit. On a Coleman Mach the box sits beside the compressor and holds the run capacitor for the compressor, the run capacitor for the fan, and on many models a start capacitor, which is a black plastic cylinder wired through a small relay. On a Dometic Brisk II or Penguin II the box is on the side of the base pan and usually holds a run capacitor and a start capacitor. Some units use one dual run capacitor with three terminals. Others use two or three separate capacitors. Replace only the one that fails the test, and photograph everything before you pull a wire.

How to read the rating and match it

The label on the capacitor gives you everything you need. The first number is the capacitance in microfarads, written as MFD or µF, and it is the number you must match exactly. The second number is the voltage rating in VAC. You can use a capacitor with a higher voltage rating than the original, but never a lower one. A dual run capacitor shows two capacitance numbers, for example 40 plus 5 µF, and has three terminals marked C for common, HERM for the compressor, and FAN for the fan motor. The larger number goes with the compressor and the smaller with the fan (Wikipedia, motor capacitor). Part numbers matter less than the rating. A Coleman Mach or Dometic branded capacitor and a generic motor run capacitor with the same MFD and voltage rating do the same job.

The steps

1. Kill every power source. Unplug shore power at the pedestal, shut off the generator, switch off the inverter, and switch off the air conditioner breaker in the RV's panel. Then turn the thermostat to cool and confirm nothing happens.
2. Get on the roof safely. Use a ladder rated for your weight, have someone hold it, and work only on a dry roof. Do not go up if your RV's roof is not rated for a person's weight.
3. Remove the shroud. Take out the shroud screws and lift the plastic cover straight up. Set the screws somewhere they cannot roll off the roof.
4. Find the capacitor and discharge it. Open the metal electrical box on the side of the unit. Discharge each capacitor with a discharge resistor across its terminals, then confirm with a multimeter that the terminals read close to zero volts before you touch them.
5. Photograph the wiring and read the label. Take a clear photo of every wire on every terminal. Write down the microfarad rating, the voltage rating, and the tolerance printed on the capacitor label. On a dual capacitor, note which number belongs to the compressor terminal and which to the fan terminal.
6. Test the old capacitor. Set a multimeter to its capacitance setting and read each capacitor with the wires removed. A reading outside the tolerance on the label, a bulged top, or oil on the case means the capacitor has failed. If it tests good, the capacitor is not your problem.
7. Install the matching capacitor. Fit a replacement with the same microfarad rating and a voltage rating equal to or higher than the original, then move each wire to the same terminal it came from, using your photo.
8. Reassemble and test. Close the electrical box, reinstall the shroud, restore power, and run the unit on cool. Listen for the compressor to start and feel for cold air at the ceiling vent within a few minutes.

On the test in step six, HVAC School's bench test rule is that if the reading is more than 10 percent off the rating, replace the capacitor. HVAC School also says the replacement must be the same MFD rating, that you may use a higher voltage rating but never a lower one, and that a top that is bubbling or a case that is leaking oil is reason enough to replace it on sight (HVAC School). If your meter has no capacitance setting, buy one that does. They cost less than the capacitor, and it is the only way to know rather than guess.

Two Coleman Mach notes. Many Mach units have a start capacitor and a start relay next to the run capacitor. A start capacitor that fails gives the same hum-and-quit symptom as a bad run capacitor, so test both. And if the run capacitor reads within tolerance but the compressor still struggles to start on a weak power supply, a hard start kit is a common add-on, but it is a bandage for low voltage, not a fix for a failed compressor.

If any part of this is beyond you, stop and call a tech. At Agile's rates, that is a $150 service call plus labor at $150 per hour, and you still come out hundreds of dollars ahead of a new unit.

When is replacing an RV air conditioner the right call?

Replace the unit when the compressor has failed, when there is a leak in the sealed refrigerant system, when an older unit has had repeat failures, or when the repair estimate is more than half the price of a new unit installed. Anything else on the list above is a repair. Here is how to recognize each of the four.

A failed compressor. The compressor is sealed inside the unit and is not replaced on its own on a rooftop RV air conditioner. When it seizes, shorts, or trips its overload every time with good voltage and a good capacitor, the unit is done. Make sure the voltage and the capacitor were actually tested, because both mimic a bad compressor.

A leak in the sealed refrigerant system. Rooftop RV units are built as closed, sealed systems with no service ports. As one Coleman Mach parts retailer puts it, they are designed as closed and sealed systems and ideally should never require recharging, and a low charge means a leak that should be handled by a professional (HVACpartstore). Under federal rules, anyone who opens the refrigerant circuit, including attaching gauges or adding refrigerant, must hold EPA Section 608 certification (EPA, Section 608 technician certification). We give no instructions for adding refrigerant here, on purpose. In practice, a tech who finds a leak in a rooftop unit will quote you a new unit, because tapping the system, finding the leak, repairing it, and recharging costs more than the unit is worth.

An older unit with repeat failures. A capacitor on a unit that has never given trouble is a repair. A capacitor this year, a fan motor last year, and a freeze up problem the year before is a unit telling you it is worn out. Each of those parts cost you money and a hot weekend. Add them up before you buy the next one.

Repair cost above half the price of a new unit. Use the table above. If the quote for the repair, parts and labor together, is more than half of what a new unit installed would cost you, put the money toward the new unit. A fan motor and a control board on the same visit, installed by a tech, can cross that line. A capacitor never does.

How does an RV air conditioner replacement work?

The old unit comes off the roof, the new one bolts down over the same square opening on a new gasket, and the ceiling assembly and thermostat inside are reconnected or replaced to match. A mobile tech or shop does it in one visit. The new unit must match your roof opening, ducted or non-ducted air delivery, and your controls.

The roof opening. Nearly every rooftop RV air conditioner mounts over the standard 14 inch square opening, the same opening a roof vent uses. Dometic's installation manual calls for a 14 1/4 inch square opening, within an eighth of an inch, and says the roof needs rafters or support frames on 16 inch centers to mount the unit properly (Dometic installation manual). That standard is why you can put a Coleman Mach where a Dometic was, or the other way around, as long as the rest matches.

Ducted or non-ducted. A ducted RV has ceiling ducts running to vents around the coach, and the air conditioner pushes air into those ducts through a return air box at the opening. A non-ducted RV has a ceiling box under the unit with its own vents and controls. The rooftop unit is often the same either way. The ceiling assembly is what differs, and it must match how your RV is built. Look at your ceiling before you order.

Matching the ceiling assembly and thermostat. If you stay with the same brand and the same control type, you can usually reuse the ceiling assembly and the wall thermostat and only replace the rooftop unit, which is the $1,200 to $1,400 part in the table. If you change brands, or move from a non-ducted knob box to a wall thermostat, plan on a new ceiling assembly and thermostat with it. That is the difference between the low and high ends of the installed cost.

The roof gasket. A new unit comes with a foam gasket that seals it to the roof. The old gasket is never reused. The unit is set on the gasket and pulled down with the ceiling assembly bolts, tightened evenly to the compression the manual specifies. Overtightening crushes the gasket and cracks the base. Undertightening leaks. This is the step that decides whether your ceiling gets wet next spring. If you are reusing a unit or a tech asks you to supply one, Camping World lists a 14 by 14 inch rooftop air conditioner roof gasket kit at $57.99 (Camping World, roof gasket kit).

What a shop or mobile tech does. They disconnect power, remove the interior ceiling assembly, unbolt the old unit, lift it off the roof, clean the roof around the opening, set the new unit on its gasket, torque the bolts, connect the power and thermostat wiring at the ceiling, install the ceiling assembly, and test it on cool and heat. One retailer's installation guide says a direct replacement, swapping the old unit for a new one, typically takes 2 to 3 hours, while a first-time installation that needs cutting, wiring, and framing takes longer (RV AC Unit, cost to install). A mobile tech does it in your driveway or at the campground. A shop does it on a lift. Either way, Coleman Mach's own guidance is that a licensed, trained technician should complete the installation of any RV air conditioner (Airxcel, replacing an RV air conditioner). If you need to find one, start with our guide to finding a mobile RV tech near you.

What should I know about my specific model?

The five units below are the rooftop models this guide covers. For each one we list only what a manufacturer, a retailer, or a recall record actually documents. Where we could not find a citable source for a known failure, we say so instead of repeating forum rumor.

Dometic Brisk II

The Brisk II is Dometic's standard profile rooftop unit, and its two stock repair parts are the ones this page is about. Retailers sell the 60/5 MFD, 370 volt run capacitor (Dometic 3312195.000) as the replacement for the Brisk II family including the B59516 (Panther RV Products), and the 3315332.005 fan motor as the direct replacement for the B57915 and B59516 (RV AC Guys). Dometic also sells a freeze control sensor for the Brisk and Penguin II models (part 3309191.009), which is the part to check on a unit that keeps icing up with clean filters (High Sky RV Parts). One recall to know about: NHTSA recall 17V-620 covered 2017 and 2018 Grand Design Imagine trailers whose air conditioner wires could detach from the connector and short circuit, fixed by installing positive retention connectors (NHTSA recall 17V-620 record). Owner forums tie that recall to the Brisk II 15,000 BTU unit, but the recall record itself does not name the air conditioner brand. On a Brisk II, the capacitors sit inside the electrical box under the shroud, which is held on by four screws (Micro-Air EasyStart installation guide for Dometic units).

Dometic Penguin II

The Penguin II is the low profile Dometic unit. The Dometic 3316230 single zone thermostat with control board is listed as compatible with the Penguin II 640310C, 640315C, and 640316C, and it is the part a tech installs when an older relay board fails (Panther RV Products). Elkhart RV Parts sells Penguin II drain kits and a drain pan system made to carry condensation away from the roof and the interior (Elkhart RV Parts), which tells you water management on this unit is worth checking when you see drips at the ceiling. Owners on the iRV2 forum report the freeze sensor falling out of the evaporator coil as a cause of freeze ups, and that is an owner report, not a manufacturer statement (iRV2 owner thread). We found no recall for the Penguin II.

Coleman Mach 15

The Mach 15 is Coleman's high output standard profile unit, and it has one documented quirk worth checking before you buy any part. Camping World's repair guide says the terminal connectors on the outside of the Coleman Mach control board box can develop light oxidation that causes a loss of connectivity, and that removing and reinstalling the terminals three or four times can clean them up and restore the connection (Camping World repair guide). Coleman Mach's own installation instructions warn that any length of ducting reduces evaporator airflow and creates the potential for freeze up (Coleman Mach installation instructions), so a ducted Mach 15 that ices up needs its airflow checked first. For a compressor that struggles on generator or weak campground power, Coleman Mach sells a hard start kit, part 8333A9021, that adds a start capacitor and relay without replacing the run capacitor (United RV Parts). We found no recall for the Mach 15.

Coleman Mach 8

The Mach 8 is Coleman's low profile unit, and its best documented issue is the condenser fan. Units built between mid 2014 and mid 2015 with fan hubs numbered 1472B504 or 1472C504 had blades that failed at the root, threw the fan out of balance, and broke the motor mounts, and owner forums reported a 1472D504 replacement fan kit available under warranty (Forest River Forums owner alert). The current part is the 1472D504 fan blade kit, sold as the replacement for the original equipment condenser fan blade on Mach 8 units (RV Upgrade Store, fan blade kit). On water, not every Mach 8 left the factory with a condensate pump. Coleman Mach publishes installation instructions for kit 47233-309 specifically to add a condensate pump assembly to a Mach 8 that was not factory equipped with one (Coleman Mach condensate pump instructions), so if yours drips onto the roof, find out which version you have before you start chasing a leak. Coleman Mach also publishes replacement instructions for the Mach 8 motor run capacitors, and their test is the same one described above: if the motor will not start on any speed but runs when you spin it by hand, replace the run capacitor, and if it still will not start, the winding is open and the motor needs replacing (Coleman Mach capacitor replacement instructions). We found no recall for the Mach 8.

Furrion Chill Cube

One naming note first. Retailers list the FACR15SA as the Furrion Chill 15,500 BTU rooftop unit (High Sky RV Parts), while Lippert's own support library documents the Chill Cube ducted system and the Chill variable speed units as separate product lines with their own manuals (Lippert Customer Care Center, air conditioning documents). If a shop quotes you a Chill Cube, confirm which unit is actually on your roof before you pay for it. The best documented problem on Furrion systems is a thermostat one. A Forest River service bulletin filed with NHTSA in April 2025 describes a compatibility issue between the Furrion wall thermostat and the Furrion control box that causes an E3 error code, with the fix being a Furrion single zone thermostat (NHTSA technical service bulletin MC-11016856). Lippert publishes its own document on correcting the E3 error (Lippert QR-187). On water, etrailer's product experts say Furrion units leaking condensation into the RV are either clogged drain openings or a damaged roof gasket (etrailer expert answer). We found no recall for the Furrion Chill or Chill Cube.

What else do RV owners ask about repairing or replacing an AC?

The questions below are the ones owners ask once they have been told they need a new air conditioner. Each answer stands on its own, and each one points back to the same rule: rule out the cheap parts before you pay for the expensive one.