# 240/12v problem



## riverrver (Apr 12, 2011)

Hi, when I hook my Chausson motorhome up to the mains only the power sockets work & nothing else.......no control panel, no interior lights.

anybody got any ideas?

Thanks


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## Penquin (Oct 15, 2007)

1. Is the control panel switched on (OK silly question)

2. it sounds like there is a fuse link somewhere that has blown, perhaps near the battery?

3. does it work without the EHU?

4. on your control panel do you have a switch to allow you to draw current from the vehicle battery rather than the leisure battery? If so and that works then the fault lies on the leisure battery side..

5. if nothing works at all then somewhere there is a broken link - fuse or bad connection but do you have a 12v meter that you can check where the power is getting to, if anywhere?

Just a few thoughts...

Dave


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## riverrver (Apr 12, 2011)

Thanks for your speedy reply.



3. if I disconnect the mains and start the engine, the control panel & interior lights work ok.


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## riverrver (Apr 12, 2011)

how does the 240/12v conversion work in these vehicles.

is it....

1. the 240v enters some kind of converter & then 12v is dispersed to the CP & IL


or 

2. does the 240v charge the leisure battery & then it takes care of dispersing the 12v?


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## flyinghigh (Dec 10, 2012)

I had a slightly corroded fuse by the leisure batteries that gave the same symptoms,
Clean fuse and all back to normal,it's the 12 volt feed to the control panel you need to look at,


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## Penquin (Oct 15, 2007)

The 240v enters the van and goes into a big transformer, from there the 12v feed goes to the battery. The battery feeds via the wiring to the control panel and the control panel then controls ( :roll where it goes e.g. pump, lights etc....

There is also a relay in the engine compartment which means that 12v from the engine goes to the back when the engine is running for e.g. the fridge - which can ONLY work on 12v when the engine is running.

If the lights etc. are only working when the engine is operating then the feed from the leisure battery is not getting to the control panel and the most likely reason is a blown fuse of a broken connection. There is often a fuse near the battery in the wire from the battery (the red one) which may be loose or blown - if you look at the fuse you should be able to see the wire being intact. But try replacing it with another of the same rating. DO NOT USE THE WRONG VALUE FUSE.










there are other designs of fuses, but that one is quite commonly found. The wire across the middle can be clearly seen, if the fuse is blown that wire is not continuous.

That would be where I would concentrate looking, it may be near the battery or even in a fuse box for the MH, but is unlikely to be in the original vehicle boxes.....

Dave


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## riverrver (Apr 12, 2011)

There was no fuse near the battery so I replaced the 12v auxillary fuse in in the main fuse box.

still nothing.

if the leisure battery is completely dead.....would this explain the problem?


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## djp30 (Jan 9, 2012)

riverrver said:


> There was no fuse near the battery so I replaced the 12v auxillary fuse in in the main fuse box.
> 
> still nothing.
> 
> if the leisure battery is completely dead.....would this explain the problem?


Probably, most chargers these days will not give an output if they can't sense a voltage, so they need above 10v to work.


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## 91502 (May 1, 2005)

Have you checked the voltage of your leisure battery?
If this was dead you would get the symptoms you describe. 
James


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## Penquin (Oct 15, 2007)

Have you got a voltmeter so that you can trace where the 12v is live?

The battery should read around 12.4v, but if it has no reading then it is dead and will not recover......

The negative (black) lead of the voltmeter goes on the terminal marked - the positive (red) lead goes on the battery terminal marked +

It is important that the voltmeter is set to volts and also to 20v maximum, that way you get a clear deflection if it is a needle display one and a digital readout if it is digital.

If you have not got one, can you borrow one? They are cheap instruments to buy (upwards of about £5) and the absolute accuracy does not matter, so a cheap one will do IMO.

I have two - one digital and one needle and that gives me multiple chances to do things...... but it is abit far away for you to borrow....

Dave


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## riverrver (Apr 12, 2011)

just borrowed one and set it to 20dcv......it measured between 000 & 001 on the leisure battery.

:lol:


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## 91502 (May 1, 2005)

Has it been stood for a while?
Something must have been left on to drain it that much. 
I doubt that the battery will recover from dropping that low.


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## vicdicdoc (May 14, 2005)

With a (nil) voltage reading as you describe - it sounds like your leisure battery is just like the parrot in Monty python - DEAD :?

(Cheer up, worse things can happen :wink: if it is the battery - at least its easy to rectify


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## Mrplodd (Mar 4, 2008)

It has ceased to be, it is no more, it has shuffled off its mortal coil,

ITS DEAD :lol: :lol:


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## Penquin (Oct 15, 2007)

As I said earlier, if that is the reading you are getting then that battery is dead.

Enjoy, I did,

Dave


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