Dometic Freshlight
Official technical documentation and workshop diagnostics for Freshlight.
View official manual on manufacturer's site ↗Technical Specifications
Master Troubleshooting & Diagnostics Matrix
| Error Code / Indicator | Symptom / Meaning | Possible Cause | Step-by-Step DIY Fix | Suggested Actions |
|---|---|---|---|---|
N/A | The roof air conditioner keeps switching itself off | The icing sensor's tripped, either from too-low outside temperature or all the air nozzles being closed | Ensure ambient temperature is within operating range and open air nozzles. | DIY Safe |
N/A | No cooling capacity | Unit not set to cooling, ambient temperature above 52 °C or below 16 °C, temperature set higher than room temperature, defective temperature sensor, or damaged vaporiser/condenser fan | Set unit to cooling, ensure ambient temperature is between 16 °C and 52 °C, select a lower temperature, or contact an authorised workshop for defective sensors and fans. | DIY Check / Tech Fallback |
N/A | No heating capacity | Ambient temperature above 30 °C or below 2 °C, temperature set above 30 °C, unit not set to heating, or defective temperature sensor | Use heating function only when ambient temperature is between 2 °C and 30 °C, select appropriate temperature, set unit to heating, or contact an authorised workshop. | DIY Check / Tech Fallback |
N/A | Low air output | Either the air intake's clogged with leaves and dirt, or the blower's faulty | Remove debris from ventilation grilles or contact an authorised workshop if blower is defective. | DIY Check / Tech Fallback |
N/A | Water enters the vehicle | Either the condensation drainage openings are clogged, or the seals are damaged. | Clean drainage openings for condensation water or contact an authorised workshop to replace damaged seals. | DIY Check / Tech Fallback |
N/A | The roof air conditioner won't switch on | No supply voltage connected, voltage too low (under 200 V), defective voltage converter, defective temperature sensor, or electrical fuse too low | Check power supply, verify electrical fuse ratings, or contact an authorised workshop for internal electrical/sensor faults. | DIY Check / Tech Fallback |
N/A | The roof air conditioner won't switch off | Either a temperature sensor's faulty, or the power supply's electrical fuse is low | Check electrical fuse or contact an authorised workshop for sensor replacement. | DIY Check / Tech Fallback |
Frequently Asked Questions
Q: Why fit air conditioning to a motorhome or caravan?
Comfort depends on humidity as well as temperature. We can tolerate up to about 26°C (78°F) only when the air is dry; in humid air, around 20°C (68°F) is the comfortable limit. Most people feel best at roughly 18-22°C (64-72°F) with 40-70% relative humidity. Achieving that in a motorhome means cooling the air and drying it at the same time, which needs a compressor air conditioner - systems relying on direct or indirect evaporative cooling are less effective.
Q: What temperature should I set the air conditioning to?
How warm the air feels can differ from what the thermometer says, and humidity makes a big difference. In dry heat, sweat evaporates quickly from the skin and cools us, so we cope with high temperatures; in humid heat, sweat evaporates less, so we feel hotter, and the damp, sticky air can affect circulation and sleep. That's why a good air conditioner needs to lower the humidity as well as the temperature. Dometic suggests around 26°C (78°F) is usually comfortable.
Q: How powerful an air conditioner do I need for hot countries?
If you mostly tour in cooler climates, the air conditioner won't be pushed hard and a lower-rated unit will be enough. If you regularly travel somewhere hot - especially with children or pets on board - don't skimp on output, as a motorhome or caravan can quickly get uncomfortable on a hot day, and when nights stay warm too, you'll only rest properly with an adequately sized unit.
Q: How does motorhome air conditioning work?
Much like a household fridge, but far more powerful: a refrigerant draws heat out of the space being cooled and releases it outside - and in a motorhome or caravan it should also reduce the humidity. Evaporative systems are a common alternative: a roof-mounted unit evaporates water into a filter, and a fan pulls outside air through it so heat is exchanged.
They use little power and are light, but their effectiveness depends on the outside humidity, so performance varies - it falls away above 85% humidity, exactly when cooling is most needed - and they always add humidity inside the vehicle, whatever the conditions. Caravans and motorhomes don't have thick walls like a house, so even well-insulated ones heat up in the sun, easily reaching 30°C or more inside - in temperate climates as well as hot ones.
How hot it gets also depends on window size and number (small windows heat up more slowly than large glazed areas), on whether you're parked in sun or shade, and on whether you air the vehicle out or keep everything shut.
Q: Can I run my air conditioner from a generator?
Yes - a generator gives you a reliable power supply wherever there's no mains hook-up, so you can keep your home comforts when touring off the beaten track. Dometic makes generators for exactly this.
Q: Can I run my air conditioner on a campsite hook-up?
Usually, yes. An air conditioner draws more current at start-up than any other appliance you're likely to have on board, but only for a fraction of a second - it uses far less once it's running. Most campsite hook-ups are protected by a time-delay fuse, so those brief peaks don't normally cause a problem.