# Urgent help required - Short circuit on side lights



## SueandRoger (Apr 14, 2008)

Arrived in Austria yesterday but on the way down, the left hand side lights on my Fiat Hymer fused, the right side are ok. I could not see anything obviously wrong so replaced the 5 amp fuse and as they were still working after a couple of hours and it was a hot sunny day, I switched them off.

Later as I was driving with the lights still switched off, I noticed the side and headlight indicator on the instrument panel come on for a few seconds before going off; I therefore tried the side lights and the same fuse for the left side had blown again; all other light are still ok.

I am guessing that it is a short on the left side light circuit so would this happen if the positive leads went to earth or would it require another live circuit to come in contact with the side light circuit to illuminate the side/headlight indicator on the instrument panel?

I am staying put for about 8 days but will then be working my way back home so need to get them fixed beforehand.

Thanks in anticipation of hopefully, a solution.


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## cabby (May 14, 2005)

I would assume it is either a faulty bulb or bulb holder, or even corroded conector on bulb holder.
I would take out the all side lights bulbs on that side and with each one in turn see which blows the fuse and then investigate that unit.


good luck and hope this helps

cabby


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## inkey-2008 (May 24, 2008)

If as you say the lights are switched off and the fuse is blowing then it has to be in the control side of things. 
It could be the stalk (if the light switch is on the stalk) where you using the indictor when it blew or anything else. 

Is something else on that circuit. Some time you find 2 or 2 circuits share the same fuse. 

Andy


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## cabby (May 14, 2005)

If brake lights are in the same bulb as the rear lights then include this in test.

cabby


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## teensvan (May 9, 2005)

Hi.

Take a very close look at the wiring where it goes into the light units or where any wires pass through any of the bodywork.

steve & ann. -------- teensvan


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## kandsservices (Sep 5, 2010)

As cabby has posted check the brake light bulbs if it is the same bulb as the side lights i had a car once light up the dash lights when the brakes were applied found the filament had inter connected to the side light filament inside the bulb.
kev


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## SueandRoger (Apr 14, 2008)

Thanks for all your suggestions so far: I wasn't using the indicators or the brakes, just had the ignition on,

Problem that I have at the moment is that for the last 12 hours about 30 cm of snow has fallen and the forecast shows that it likely to continue for at least the next 24 - 48 hours; once I get chance I will check all the bulbs and holders as suggested.

A long time ago I also had a bulb where the brake light filaments made contact with the side light filaments so that will also be checked.

Main question I would like the answer to is, would there have to be another live cicuit come in contact with the side light circuit or could the light on the instrument panel come on just by the positive side of the side lights being earthed?

I have limited wifi here so will log on again tomorrow evening.

Thanks again.


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## cabby (May 14, 2005)

as the fuse did not blow straight away, it would suggest that there is a resistance somewhere that builds up and it could be any number of the faults mentioned.
rather that try to guess what is wrong,a simple sequence of testing the circuits will provide results, maybe slowly, but eventually.I only ask if you had any work or had anything extra added to the vehicle recently, such as a tow bar, or an extra stop light.if this is the case it could mean you need to upgrade the fuse.

cabby

ps enjoy the snow, we only have rain and a frosty mist all day.


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## gaspode (May 9, 2005)

Have you checked that none of the light units are full of water or condensation? That might explain intermittent fusing - ie: when the water sloshes about in the unit or condensation drips down the glass and shorts the terminals.


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## SueandRoger (Apr 14, 2008)

Thanks Cabby/ Ken

I have had nothing electrical fitted on the van for about 2 years now so I think the fault has developed in the last week since I left home.

Yesterday was a really bad day here: had about 40 cm of snow Friday night Saturday morning and lost internet, Sky and mobile network was very poor and even St Anton was closed down to all traffic.

This morning it was fine so checked all the bulbs in the circuit and found no problems with loose wires, contacts or water ingress into light housings. I did change one of the 2 stoplight bulbs as it was a little discoloured within the glass but it was working ok. I also earthed the positive lead with the ignition on but lights off and that did not illuminate the sidelight indicator on the instrument panel so I guess the side light circuit is making contact with another live circuit when the ignition is on.

The fault is not happening at present and I tried everything to replicate it with the the engine on but did not move the van as sheet ice all around me after rain last night and thaw this morning.

Guess I will have to wait until we move off next week and if fault occurs I will wire left tail lights to right hand circuit and up that fuse to 7.5 amp until I get home unless anyone has any more ideas?

Where are you cabby?


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## poleman (Aug 31, 2008)

If the headlamp warning lamp flashed up is there a fault with the headlamp/ side light wiring? Powering the side lights and headlamp bulb may overload the fuse. Just a thought.


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## SueandRoger (Apr 14, 2008)

poleman said:


> If the headlamp warning lamp flashed up is there a fault with the headlamp/ side light wiring? Powering the side lights and headlamp bulb may overload the fuse. Just a thought.


Hi, By the headlamp warning lamp are you referring to the lamp in the instrument cluster that shows the lights are on, and if so, would that happen when the lights are switched off?


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## poleman (Aug 31, 2008)

No with the lights off there should be no power there. Blown fuse is as you say usually short to earth ie power wire or overloaded circuit ie corroded connection or wiring drawing too much current through corroded bulb holder etc.


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## cabby (May 14, 2005)

sorry missed you question there.
sitting in my office, until the grandchildren decend upon us then it is a bedroom again. :wink: down on the cold but bright Sussex coast, munching biscuits and drinking tea. :lol: :lol: 
hope you sort it pit.

cabby


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## SueandRoger (Apr 14, 2008)

poleman said:


> No with the lights off there should be no power there. Blown fuse is as you say usually short to earth ie power wire or overloaded circuit ie corroded connection or wiring drawing too much current through corroded bulb holder etc.


Sorry if I am being a bit thick here, but are you saying that even if the lights are switched off, the fuse could blow for the reasons you have given above?


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## SueandRoger (Apr 14, 2008)

cabby said:


> sorry missed you question there.
> sitting in my office, until the grandchildren decend upon us then it is a bedroom again. :wink: down on the cold but bright Sussex coast, munching biscuits and drinking tea. :lol: :lol:
> hope you sort it pit.
> 
> cabby


My mistake, I thought you were also over this way where it either snowing like there is no tomorrow or raining cats and dogs.
I wouldn't want sue to hear me say it, but it is nice to have a break from the grand chidren! 4 years ago I had none but now have 5 and that includes 11 week twins next door!
Just managed my first 2 hours on the slopes but had to stop as snowing again!
Not sure if I am getting anywhere with my light problem but if Poleman says the circuit can short out even with the lights off, I may have a way forward.!!


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## cabby (May 14, 2005)

If you can, wait until it is either dry or bright enough for you to fiddle.how long until you have to move.
I am going to read through the whole topic again to see what has been said before I make any further comments.I have a feeling I missed something.

cabby


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## poleman (Aug 31, 2008)

Hi Sueand Roger, No if the lights are turned off there should be no power to the lights so there can't be a feed from the headlamp circuit if the lights were turned off. The side light fuse protects the live side of the side light circuit so the problem must be on that circuit to blow the fuse. 

You would assume that if there was a dead short on that circuit the fuse would blow immediately. If the fuse blows after a longer time it's more likely to be a bad connection somewhere.

If you've checked all the lamps and connections and all are ok then the quickest way to find a bad connection is to put in a much larger fuse and wait for the offending connection to start smoking! this is only a last resort carried out with the greatest of care and close observation.


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## SueandRoger (Apr 14, 2008)

As I mentioned in my innitial post, when the lights are turned off, the side/headlight lamp on the dashboard is coming on for about 5 seconds and then when I check the 5 amp fuse, it has blown for the left hand side lights! I have checked all the bulbs/connections in that circuit and they all appear good. I therefore presume that the left hand circuit is picking up another live circuit from somewhere that is causing the problem?

The only things I have connected to the side light circuits are the tow bar electrics, which will be very difficult to investigate in these conditions, but as it is single electrics anyway, I can't see that as a problem; the other thing is the alarm system, but as that is connected to left and right circuits, I can't see that as the problem either? Any further thoughts anyone>

We were due to move off this site on Saturday but will probably stay another few days as the weather forecast looks good for next week.

Edit to confirm single electrics.


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## inkey-2008 (May 24, 2008)

Did you fit the tow bar electrics. If so did you use a bypass relay box. It has a live feed to it and that might have water in it causing a short circuit. 

I have just had to change one on my van as the indicators stopped working on the van and just by chance I unplugged the lighting board and everything started to work again. 


Andy


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## SueandRoger (Apr 14, 2008)

inkey-2008 said:


> Did you fit the tow bar electrics. If so did you use a bypass relay box. It has a live feed to it and that might have water in it causing a short circuit.
> 
> I have just had to change one on my van as the indicators stopped working on the van and just by chance I unplugged the lighting board and everything started to work again.
> 
> Andy


Hi Andy

The towbar and electrics were fitted by PWS in Poole and to be honest, I am not sure if they used a Bypass relay box! However.because I have a pull out motorcycle rack and was towing a car on an A Frame, they fitted a 'unit' under the chassis to boost the power to the indicators as they didn't think the system would work without it with so many lights. That unit is powered by a wire connected direct to the engine battery with an inline fuse. Any thoughts?


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## cabby (May 14, 2005)

Yes to any thoughts, you will have to get down to that unit and see if the snow has got in and shorting the wires out. It is the only answer that i can see after reading your posts, as you did say you had the ign on.this would have powered that unit, frayed wire or just water could have entered and created a short.Or you could have dislodged it moving the bike etc.
wrap up well when lying down.

cabby


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## inkey-2008 (May 24, 2008)

I found ours just laying on a ledge exposed to all the wet from the road. I replaced it and put it in a plastic box used for domestic electrics. 
You could try pulling the fuse it you are not pulling a trailer.

Andy


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## SueandRoger (Apr 14, 2008)

Just got back from my daily 20 lengths in the extremely nice free indoor pool on the site and thought I would take that fuse out of the forementioned circuit! However, the bonnet is firmly welded shut with ice and we are not due a thaw for a couple of days; -11c forecast for tonight! It is certainly feasable that the unit in question could be causing the problem and tomorow I will see if I can clear some of the 30 cm of snow from around the base of the camper that fell last night; skiing clothing required me thinks.

Thanks for all your help and I will keep you informed of what I find in that unit if I can get into it. Problem is, as this is an intermitent problem and it is not happenning at this very moment while I am parked, I won't know if the problem is solved until I have driven for a day or two.


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## inkey-2008 (May 24, 2008)

Never to be heard of again.!!! Still stuck in the snow.

Andy


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## SueandRoger (Apr 14, 2008)

Hi Andy

As it was an intermitten fault I was waiting until I had been up to Breckon next week before I gave an update on the sidelight fault as it didn't occur on my way home from Austria last week!

However, when I got home I did have a good look inside that relay box for the towing electrics and could see no sign of a short circuit so I have put the fuse back in and all is fine when I run the camper up on the drive.

When I had checked the rear wiring on the left hand light cluster in Austria, I did notice that the stop/side light bulb had some corrosion on it around the two contacts on the bulb base so could it have been that when I braked, the side lights came on and that was causing the 5 amp side light fuse to blow?

The fault usually happenned on start up but some times in the middle of the run and as I have one of the very rare automatic 2.8 JTD's, putting the foot brake on before turning on the ignition may have been the fault as the brake lights have a 10 amp fuse; what do you think?


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## inkey-2008 (May 24, 2008)

I have been thinking about it, If you have a poor earth in the rear light cluster and you put the brakes on then the power to the lights needs to find an earth.

It will take the easiest route it can find, normally via another lighting circuit on the same earth point. 

You can see this when then brake lights come on, the side light bulbs light as well.

So it could be a poor earth in the light cluster or where ever that is earth back too. 

So it is possible that this is what is happening.

Andy


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## SueandRoger (Apr 14, 2008)

Thanks Andy, that sounds very feasable to me.

Having cleaned up all the bulbs and contacts in the 4 rear light clusters, I will double check the earth points as well. If it starts shorting out on our way up to Breckon next Saturday, I will get my wife to see how many of the rear lights light up when I apply the brakes at standstill and if it doesn't happen then, she will just have to lay on the 'pull out' motorcycle rack when we are driving to see if they all light up on the move. LoL


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## SueandRoger (Apr 14, 2008)

Well, the lights worked ok while we were away in Wales so I guess the problem was with poor connections/earthing; My wife was very pleased that she did not have to lay on the motorcycle rack while we were under way!

Thanks to all that offered constructive advice, it was very much appreciated.


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