Lunar internal light problem

My first question would be 'are you sure that the battery is fully charged and holding its charge? How do you know that? Are you sure that the battery has not gone duff? 

A clean break in a wire, will, as you say, prevent current from flowing, but a poor connection caused by corrosion (oxidisation)  or a lose contact, may prevent the required current (amps) from flowing. Think how a partially sink waste pipe will reduce the water flow, so that it drains slowly.

The above restriction may exist somewhere in the +ve feed which is shared by all three lamps, or on the -ve, which is also shared. Your large light may well be glowing, but so faintly due to reduced current, that’s not noticeable.

Locating the fault is likely to be difficult with a voltmeter because it may register 12 volts, despite the limited current flow. Testing is best achieved with a real bulb connected to two separated bits of wire. Connect one wire to any known to be working point on the -ve supply. Use the battery -ve if necessary, then check whether your improvised test bulb lights properly when you touch the live feed to your switch if it does, then the fault lies in the van’s -ve return circuit. If the bulb doesn’t light properly, then the fault is in the +ve feed. Whichever half of the circuit has been found defective, you then need to bypass lengths of it with your home made tester until you have bypassed the fault. Using the tester in this way, will reduce the intensity of the bulbs glow because the bulbs will be connected in series. BUT, it will serve to save you from inadvertently blowing fuses by touching the wrong wire.

If the above is double Dutch to you, then you might be safer getting someone with more experience of working with electricity to help. Motor mechanics are notorious for their inability to understand electrical circuits, so when you’ve found one that does, make an indelible note of his contact details.

Good luck.

Hello Easy T the battery is almost new and showing 13.6volts the van is hooked up to mains. As in op everything else is working perfectly the fault is just showing on these lights alone.

P

Certainly sounds like a poor connection in the wiring. I had something similar on previous Lunar affecting some lights towards the front. Seemed likely to be a poor connection as the fault was intermittent. Arrive on one site and a couple of lights not working. Arrive on next and everything worked etc. Turned out to be a poor connection hidden beneath the microwave. 

Ok thanks for the replies. I'll get probing, though it's  not something that can't  be lived with. If I  get stuck it might have to wait till service time. I'll report back,

Cheers, Paul 

I have tended to use the unscientific wangling method. 

I have waggled (or should that be wiggled?) wiring about until a light flickers to narrow down/locate such problems.

I have a 2015 Lunar Quasar 524 derivative (dealer special). Since new I have had an intermittent fault with the two centre ceiling lights. Sometimes they work and sometimes they don't. It is always both, not just one of them. Sometimes they are OK when I set off on a journey but have failed upon arrival. At other times it is the other way round. Sometimes, though, if they are in the failed state, if I leave them switched on they will suddenly come on after several minutes. I have been told that it would be a very lengthy job to try to find the source of the problem which might, I'm told, involve taking the ceiling panelling down. For the number of times we use the lights I've decided to leave things as they are as I didn't want to be without the caravan for an indeterminate length of time.

It's interesting that others have a similar problem with their Lunar. If anyone can pinpoint where the fault probably lies I'd be keen to know. Is it just a Lunar issue?

 I suspect that most joints are accessible somewhere rather than hidden in the ceiling. In my case it meant removing the microwave.

I have one light in lounge and one in bedroom not working and tested by swapping complete lights with one that work. pointed out to lunar at service that its a wiring fault but stated that its not covered after first 12 months. ridiculous. tried to sell me a new shower light at £65 and a front nearside road light as a bit dim. removed myself, cleaned and ok. took 5 mins. I think Campbell's engineers a bit DIM.

I had the same on one of my LED downlights (Lunar Ultima 560) checked the wiring near the lamp and found a bad connection. Sorted this out and light works perfect.