When caravan lights stop working, the issue isn’t always obvious. One light might fail while others work fine, or everything might suddenly go dark. Because caravan lighting relies on the 12V system, even small faults can cause confusing symptoms.
The good news? Most lighting problems are simple to diagnose once you approach them logically.
This guide walks you through diagnosing both interior and exterior caravan lighting issues, step by step — without needing advanced electrical knowledge.
What You’ll Learn
- Common causes of caravan lighting failures
- How to diagnose interior lighting issues
- How to diagnose exterior lighting issues
- When to stop DIY checks and call a professional
This guide is suitable for all caravan owners, including beginners.
How Caravan Lighting Systems Work (Quick Overview)
Most caravan lights:
- Run on the 12V system
- Are protected by individual fuses
- Share common earth (ground) points
Interior and exterior lights may be on separate circuits, so one can fail while the other still works.
Step-by-Step: Diagnosing Interior Lighting Problems
1. Check if Other 12V Systems Are Working
Before focusing on lights, check:
- Water pump
- USB outlets
- Control panel display
If nothing works, the issue is likely the battery or main 12V supply.
2. Check the Lighting Fuse
Interior lights usually have their own fuse.
Check:
- Fuse is intact
- Correct amperage is fitted
- No signs of heat damage
Replace blown fuses only with the correct rating.
3. Test the Light Fitting
If only one light isn’t working:
- Swap the LED or globe with a known working one
- Check the fitting for loose wiring
- Look for corrosion or moisture
LEDs fail more often than wiring.
4. Inspect Switches and Connections
Loose or failed switches can stop power flow.
Check:
- Switch clicks firmly
- No flickering when toggled
- Wiring behind switch (if accessible)
Step-by-Step: Diagnosing Exterior Lighting Problems
Exterior lights are more exposed to weather and vibration, so faults are common.
5. Check Tow Vehicle Connection
Many exterior lights rely on the tow vehicle.
Check:
- Trailer plug is clean and seated properly
- Pins aren’t bent or corroded
- Plug hasn’t worked loose
Wiggle tests often reveal intermittent faults.
6. Inspect Wiring and Earth Points
Exterior lights often fail due to:
- Broken earth connections
- Damaged wiring under the van
- Water ingress
Earth faults can cause lights to flicker or fail entirely.
Common Lighting Problems and Likely Causes
| Symptom | Likely Cause |
| All lights off | Battery or main fuse |
| One light off | LED or fitting |
| Flickering lights | Loose connection or earth |
| Exterior lights fail | Trailer plug or wiring |
| Fuse keeps blowing | Short circuit |
When to Stop and Call a Professional
Book a service if:
- Fuses keep blowing
- Wiring insulation is damaged
- Lights fail intermittently while driving
- You’re unsure about earth points
Electrical faults can worsen if left unresolved.
Key Takeaways
- Start diagnosis at the system level, not the light
- Interior and exterior lights often fail for different reasons
- Earth faults are common and overlooked
- Simple checks fix most issues
Next Steps
If lights are failing due to low voltage or inconsistent power:
👉 How to Check Caravan Battery Health Using a Multimeter
If lighting issues persist or feel unsafe:
👉 Service option: Book a professional caravan electrical inspection
