Strange issue today (1 Viewer)

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lorger

LIFE MEMBER
Jul 11, 2008
9,973
92,608
Dumfries
Funster No
3,262
MH
Knaus Sun 650MEG
Exp
2007
We’ve been away this weekend to Burrs country park, no issues with anything, packed everything away and headed home. When we stopped for lunch we notice our dining area lights coming on then dimming down and off, then it continued to repay this. I removed the switch which has four light switches on it, once removed I pressed the dimmer but it just continued. I then turned my 12v off using isolation switch until home, once home I turned everything back on and all was fine for a few minutes then it started again. I then removed the front and it’s like a small motherboard with about 4 or 5 wires connected.
It’s a 2020 Knaus Sun Ti 650 MEG platinum.

Anyone any ideas ?
 
Feb 5, 2020
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Was a Newbie but getting the hang of it now.
Can't help on the light problem.
But It's a bit of a bummer when you've had a great weekend by the sound of it then you get a problem.
Hope you get it sorted soon.
 

Nedge68

Free Member
Feb 28, 2022
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Barnard Castle, UK
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Sounds like a faulty dimmer switch, has it got damp at all? if it is easy to disconnect you could leave it somewhere dry and warm for a while and then try it again, turn of off the supply before removal/install of course. Some photos might prove helpful.
 
Feb 22, 2008
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Mine is not a coach built but I have overhead light in cab that is linked to drivers door which operates when door opened and fades when closed, just wondered if yours has a similar link.
 
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lorger

lorger

LIFE MEMBER
Jul 11, 2008
9,973
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Dumfries
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3,262
MH
Knaus Sun 650MEG
Exp
2007
Mine is not a coach built but I have overhead light in cab that is linked to drivers door which operates when door opened and fades when closed, just wondered if yours has a similar link.
No this is the lounge area lighting, we have two in that area one normal overhead set of lights and the other one is mood lighting or some fancy name, it's this one thats started misbehaving.
 
Aug 26, 2008
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Intermittent voltage drop from the leisure battery, perhaps due to a loose cable/terminal. My guess.
 

meanders

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Jun 28, 2008
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Do the lights fade on or snap on at full level?
Do you have a physical switch to control these lights or only the dimmer? If a switch, is it off?
If a dimmer, is it rotary?
Does you panel show the voltage in the leisure battery? If so what does it report when the fault is not present Vs it happening?
Are they LED or filament lamps?

If LED I suspect it's the dimming circuit. It will almost certainly have a capacitor. Something is charging it, the lights come on, it slowly discharges and they fade down to a level and usually snap off at about 10%. The charging restarts and at about 50% the lights come on again.

Do you have a multimeter? If so check the voltage on the back of the dimmer over a couple of cycles. If it slowly increases, the lights come on, then starts to drop as power is drawn until they go out, then that's what's happening. You then need to remove the power feed from the switch, and monitor that to ensure it's nothing on the feed. With the power disconnected, I would only expect to see a constant voltage.

Remember, while it's only 12v, getting it anywhere near earthed metal will make a spectacular spark and is to be avoided.

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lorger

lorger

LIFE MEMBER
Jul 11, 2008
9,973
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Dumfries
Funster No
3,262
MH
Knaus Sun 650MEG
Exp
2007
Do the lights fade on or snap on at full level?
Do you have a physical switch to control these lights or only the dimmer? If a switch, is it off? Its a button you press once to turn on and once to turn off, if you want to dim you press it in.
If a dimmer, is it rotary? As above
Does you panel show the voltage in the leisure battery? If so what does it report when the fault is not present Vs it happening? I haven't checked this so will have a look tonight
Are they LED or filament lamps? LED

If LED I suspect it's the dimming circuit. It will almost certainly have a capacitor. Something is charging it, the lights come on, it slowly discharges and they fade down to a level and usually snap off at about 10%. The charging restarts and at about 50% the lights come on again.

Do you have a multimeter? If so check the voltage on the back of the dimmer over a couple of cycles. If it slowly increases, the lights come on, then starts to drop as power is drawn until they go out, then that's what's happening. You then need to remove the power feed from the switch, and monitor that to ensure it's nothing on the feed. With the power disconnected, I would only expect to see a constant voltage. I will have to check this as the switch has four different sets of lights i would have to work out what feeds what.

Remember, while it's only 12v, getting it anywhere near earthed metal will make a spectacular spark and is to be avoided. Thanks for the reminder, as I'm not an electrician I always disconnect the mains/12v before working on them
Firstly thanks for the reply, I've tried to answer your question best I can. Sorry I've put it in bold, I'm not shouting just can't work out how to change colour :).

The van is just a few months out of warranty but Don Amotts are going to get a technician to call me to see if he can assist.

I've also mentioned it to a control guy at work this morning, he thinks it might be the switch is either goosed or faulty connection.
 

Gellyneck

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Jun 5, 2014
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More than toes wet now!
Everybody seems to have missed the obvious reason. Toooooooooooooo many beers in The Brown Cow when leaving the site!:getmecoat:

Apart from that I would go for a faulty dimmer switch.
 

Lenny HB

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Oct 18, 2007
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On the coast in West Sussex
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Carthago Compactline
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Since 2008 & many years tugging
Perhaps Lenny HB can shed some light (soft white) on the problem💡
Not really, probably a faulty component on the dimmer PCB.
Might be worth blasting with a hair dryer in case it's due to condensation.

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Last edited:
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lorger

lorger

LIFE MEMBER
Jul 11, 2008
9,973
92,608
Dumfries
Funster No
3,262
MH
Knaus Sun 650MEG
Exp
2007
Not really probably a faulty component on the dimmer PCB.
Might be worth blasting with a hair dryer in case it's due to condensation.
This is what my work control guy suggested, he is going to get me a spray that will clean it also.
 

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