Caravan Air Conditioner Problems: Here's Help

Jul 12, 2025

Sweating in your socks inside a “cool” caravan? You’re not alone. Caravan and Motorhome Air Conditioning problems are surprisingly common—usually power, filters, or low refrigerant. The fix might be easier than you think. Stick around for quick checks, clever tips, and when it’s time to call in the pros.

Problem: The Air Conditioner Won't Turn On

Check Your Power Source (Shore Power, Generator, Fuses)

Power issues are one of the most common causes of a non-functioning air conditioner. Faulty connections or blown fuses are often to blame.

Start by checking your caravan's electrical system. Inspect all connections and ensure the fuse hasn’t blown. If necessary, reset the circuit breaker or replace the fuse to restore power.

Inspect the Thermostat and Remote Control Settings

The thermostat and control panel play a key role in the system’s operation. If either of them malfunctions, the air conditioner might not turn on.

Check that the thermostat is set correctly and the remote control responds. If there's still no response, recalibration or replacement may be required. This is often an easy fix if caught early.

When to Suspect a Wiring or Control Board Issue

If everything else checks out but the unit remains unresponsive, a deeper electrical fault could be the issue. Wiring problems or a failed control board can prevent startup.

Watch out for any burnt smells, unresponsive buttons, or recent electrical surges. At this point, it’s best to consult a professional technician for a safe inspection.

Dometic rooftop air conditioner with dual black ventilation panels, shown in a product view on white background.

Problem: The Unit is Running But Not Cooling

How to Clean Your Filters and Coils (A Step-by-Step Guide)

Dusty filters and dirty coils are frequent culprits behind weak cooling. They block airflow and make the system work harder.

Remove the interior filters and wash them if they’re reusable. If disposable, replace them as needed. Behind the filters, gently clean the coils using a brush or low-suction vacuum to improve airflow and efficiency.

Checking for Obstructions to Airflow on the Roof

The outdoor section of your unit, usually mounted on the roof, needs good airflow to function properly. Obstructions like leaves, dirt, or other debris can block ventilation.

Visually inspect the area around the roof unit. Clear away anything that could be limiting airflow. This small action can have a big impact on cooling performance.

Signs of a Refrigerant Leak (And Why You Need a Professional)

Low refrigerant levels are another common reason your air conditioner may not be cooling properly. This can cause warm air to blow or result in slow cooling.

Leaks are not always visible. But if the cooling cycle takes longer than usual or never gets cold, a refrigerant issue may be the cause. A licensed technician must handle refrigerant top-ups and leak sealing.

Woman using Truma Aventa Compact Plus remote control while adjusting ceiling-mounted air conditioning unit inside a modern campervan.

Problem: Water is Leaking Inside the Caravan

Clearing a Blocked Condensate Drain Hose

Water leakage inside your caravan can often be traced back to a blocked drain hose. Condensation should drain away smoothly—but not if the hose is clogged.

Check the hose for debris, mould, or kinks. Clean it using water and vinegar or a soft brush. Replace the hose if it’s damaged.

The Importance of Keeping Your Caravan Level

Sometimes leaks happen even when the unit itself is fine. If your caravan isn’t level, water can pool and spill inside rather than draining out correctly.

Ensure the caravan is parked on flat ground. Even a slight angle can prevent proper drainage. This is especially important when using the unit for long periods.

Inspecting the Roof Seal and Drain Pan for Cracks

If the leak persists after clearing drains and levelling your caravan, check for damage. The roof seal and drain pan may be cracked or worn.

Inspect the sealant around the air conditioner’s base for gaps. Also, open the unit and look at the drain pan for cracks. These issues require sealing or replacing the affected parts.

Problem: The Fan Isn't Working or is Excessively Noisy

Checking for Debris or a Damaged Fan Blade

A fan that won’t spin or makes unusual sounds could be obstructed. Leaves, dirt, or even insects can get inside.

Switch off power before inspecting the unit. Look for any debris or bent fan blades. Clean out the area and carefully straighten any parts that are misaligned.

Tightening Loose Mounts to Reduce Vibration

Sometimes a noisy fan just needs a bit of tightening. Loose screws and brackets can cause unnecessary rattling.

Carefully inspect the mounting screws and brackets inside the fan housing. Tighten as needed to reduce vibration. A few turns of a screwdriver can make a big difference.

Diagnosing a Faulty Fan Motor

If the fan still won’t move after cleaning and tightening, the issue might lie with the motor itself. Humming sounds without motion are a tell-tale sign.

Fan motors can wear out over time, especially in older units. Diagnosing and replacing them is usually a job for a qualified technician.

Dometic air conditioner mounted on a white motorhome roof, with sea view and cloudy skies in the background.

Advanced Troubleshooting and When to Call a Professional

Understanding Error Codes

Common Error Codes for Dometic Systems

Dometic units often display error codes to help identify problems. For example, E1 may point to a faulty temperature sensor, while E7 could signal a fan speed issue.

Refer to the Dometic manual or manufacturer’s website for a full list. Never ignore persistent error codes—they're telling you something important.

Common Error Codes for Truma Systems

Truma systems also use digital or flashing light codes. These might relate to power failures, compressor faults, or temperature sensor errors.

Check the manual or error chart specific to your model. If you’re unsure how to interpret the code, seek help before attempting repairs.

DIY Fixes vs. Professional Repairs

Problems You Can Safely Tackle Yourself

Not every issue needs a service call. Filter cleaning, drain hose clearing, and basic visual inspections are usually safe for owners to handle.

Keep tools simple and avoid touching electrical or sealed components. Regular maintenance can prevent many larger problems down the line.

Electrical Issues and Refrigerant Leaks: Leave it to the Experts

Electrical faults, wiring issues, and refrigerant problems are serious. These can be dangerous and are best left to certified professionals.

Attempting these repairs yourself can lead to injury or further damage. If in doubt, book a qualified technician to assess the system safely.

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