12v light circuit keeps blowing fuse

EndlessSummer

EndlessSummer

Joined
Aug 16, 2021
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Hi,
Looking for some help with a 12v light circuit that keeps blowing the fuse.
It has happened a few times before then been ok for weeks but now it’s continually popping the 15A fuse(F5). I’ve tried it with all the lights switched off then pressing the light button on the control panel which puts power onto the lights and the 12v sockets (they are ok). As soon as I press the light button on the control panel the fuse pops and no habitation lights. Is an NE-185-T fuse/ control board. I’ve attached a picture of the control panel and fuse board.
Any help would be great, thanks.
 

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Are they LED lights, or incandescent type?
It does sound like a dead short on the circuit, are you able to remove the lamps then see if the breaker will stay in ? If not probably a wiring issue.If yes re-introduce them one at a time till it blows again.
I hope that's self evident.
Mike
 
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Hi,
Thanks for the reply. They are LED lights and the connections are soldered on. I have switched them all off individually but as soon as I press the power to the light circuit on the control panel the fuse pops even with them all switched off.
 
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Sounds like a dead short on the circuit then. Unusual for LED to be soldered on, it would make changing one awkward.
Mike

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if it was occasionally blowing before, then the fault has been there a while but intermittent. check the wiring behind each light and switch. Get yourself a multimeter and check the resistance between positive and negative with the power off or fuse blown
 
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Yours is a PVC isn't it?
I think you might have to try and find a mid point to the circuit and cut into it and test it from there, got any Wagos on board, or strip connectors.
Mike.
 
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So, the fitting are individually soldered to the supply circuit?
If yes, I can't think [ others might know different] of any way other than cutting into the circuit at each individual fitting of finding the fault as it could be shorting out any part of the metal body, sorry it sounds a right pain.
Are you confident enough to venture behind the main panel switch?
Mike

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BouncyBoatFolk said:
Yours is a PVC isn't it?
I think you might have to try and find a mid point to the circuit and cut into it and test it from there, got any Wagos on board, or strip connectors.
Mike.
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Hi Mike,
No wagos or strip connectors. Well nothing that I can see. I’ve had the van from new and no electrical mods done to the light circuit.
 
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BouncyBoatFolk said:
So, the fitting are individually soldered to the supply circuit?
If yes, I can't think [ others might know different] of any way other than cutting into the circuit at each individual fitting of finding the fault as it could be shorting out any part of the metal body, sorry it sounds a right pain.
Are you confident enough to venture behind the main panel switch?
Mike
Click to expand...
I’ve had a look behind the Main fuse panel and the control panel, nothing obvious. Did think it might be something on the fuse board PCB? Yip, I guess, I have cut into and re made one light fitting but no change event treated the circuit with it disconnected. Looks like I’ll have to get a bunch of connectors and check all the lights.
thanks.
 
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Desperate measures time, are you able to get behind the LED lights and ease the supply cable nearer, or pull a tiny bit of slack back.
If it's shorting on a flange edge, it might be just enough to clear any bare wire off the bodywork.
A methodical trip round the fittings is probably the best approach.
Mike
 
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The supply is going to go from the fuse to the switch first, and if the fuse is blowing with the switch off the problem must be between fuse and switch, or the switch. Switch is the easiest place to start looking as they are designed to be taken out.
 
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Have I misunderstood post #1 " As soon as I press the light button on the control panel the fuse pops and no habitation lights."
So the fuse doesn't blow until the switch is turned on, which to me would indicate the problem lies further along the circuit, if not at the actual switch?? It's certainly where my focus would be,but I could be wrong🤷‍♂️.
Mike.
 
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BouncyBoatFolk said:
Have I misunderstood post #1 " As soon as I press the light button on the control panel the fuse pops and no habitation lights."
So the fuse doesn't blow until the switch is turned on, which to me would indicate the problem lies further along the circuit, if not at the actual switch?? It's certainly where my focus would be,but I could be wrong🤷‍♂️.
Mike.
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Post 3
Hi,
Thanks for the reply. They are LED lights and the connections are soldered on. I have switched them all off individually but as soon as I press the power to the light circuit on the control panel the fuse pops even with them all switched off.

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No still not clear to me, if the fault was in the wire, from the fuse, to the master switch, the switch would never get to a stage of being ready to be switched on as the fuse would pop before the switch could be switched. If the fault lies in circuit after the master switch, then as soon as the master switch was operated with all the lights turned on or off, the fuse would pop, is my logic, but hopefully the OP will update the thread when they have ascertained the problem, I just hope it doesn't involve the removal of to much internal finishings.
Mike
 
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We have a tribute 650.
We’ve got the same control board as you.

The display in your picture is connected to a nordelektic block or something called that probably under the drivers seat behind the fuse board, there are loads of relays there that are switched from the display.

From there it runs backup inside the plastic trim and above the sliding side door and along the same on the drivers side.
If you’ve got lights under the side lockers.
Our cables run in conduit from behind the drivers seat that is where I would start first, as that is a pinch point.
It will make its way under the roof lining if you have lights on the ceiling.
All our lights switch on the fittings so if the cables are chafed somewhere it could blow even if the lights aren’t switched on.
Unfortunately you will have to check all the wiring runs.

Another thought, check behind the cupboard above the fridge that the 12v socket wires aren’t loose.
, or something hasn’t lodged in the 12v socket.
 
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Hi, thanks for all the reply’s and suggestions, really helped me out. New to this site and had problems replying. After pulling out all the lights and checking for any damage/ bare wire etc. It was eventually tracked down to a a dead short on one of the bed lights cable somewhere being the bulkhead, probably been jammed in there since built! Disconnected and replaced with new cable. Saved a hefty Bill from the garage. Thankfully didn’t have to dismantle too much panels.
Thanks again for the advice.
 
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EndlessSummer said:
Hi, thanks for all the reply’s and suggestions, really helped me out. New to this site and had problems replying. After pulling out all the lights and checking for any damage/ bare wire etc. It was eventually tracked down to a a dead short on one of the bed lights cable somewhere being the bulkhead, probably been jammed in there since built! Disconnected and replaced with new cable. Saved a hefty Bill from the garage. Thankfully didn’t have to dismantle too much panels.
Thanks again for the advice.
Click to expand...
To make life easier fault finding the short circuit I eventually found this 6 way connector block for the light circuit located behind the Main control panel. Wish I’d realised what it was earlier it would have saved a lot of time and effort🤣 Disconnected each pair individually and tested until I got the faulty line.
 

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