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yorkshireman



Member Since: 28 Mar 2016
Location: North England
Posts: 80

LED Light Bar Not Working Properly
Hi, fitted a 20" LED light bar to my Puma using the Aux Spots wiring diagram found on this forum. All looks to be correct but the light bar whilst coming on is dim to the point of barely visible. The dash light to indicate it's on is likewise on but dim. Guessing there is a failing in the circuit somewhere but not sure where to start, any suggestions please.
Post #524722 17th Apr 2016 11:45am
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custom90



Member Since: 21 Jan 2010
Location: South West, England.
Posts: 20444

United Kingdom 
Try a jury earth AKA an earth added to a good clean chassis point temporarily.
See if it makes a difference?

If not check voltage and continuity with a Multimeter and some fault tracing and finding might be worthwhile.
Post #524723 17th Apr 2016 11:48am
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yorkshireman



Member Since: 28 Mar 2016
Location: North England
Posts: 80

Thanks for the note, will try your suggestions.
Post #524726 17th Apr 2016 12:01pm
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custom90



Member Since: 21 Jan 2010
Location: South West, England.
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LED's are known to be very sensitive to voltage changes, fluctuations and poor earths.

Thumbs Up
Post #524734 17th Apr 2016 12:53pm
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yorkshireman



Member Since: 28 Mar 2016
Location: North England
Posts: 80

Hi, good news n bad. Turns out the dash switch was wired wrong, got that rectified and had momentary success with the lights coming on but then the relay blew. Could it be I need a heavier duty relay? Still need to sort the decent earth at the light end as suggested.
Post #524743 17th Apr 2016 2:02pm
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custom90



Member Since: 21 Jan 2010
Location: South West, England.
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What wattage was the light bar?
Post #524750 17th Apr 2016 2:33pm
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yorkshireman



Member Since: 28 Mar 2016
Location: North England
Posts: 80

Hi it's this one: https://www.devon4x4.com/aurora-20-led-light-bar.html

I used the relay that came with the kit.
Post #524754 17th Apr 2016 2:45pm
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Cupboard



Member Since: 21 Mar 2014
Location: Suffolk
Posts: 2971

United Kingdom 2011 Defender 110 Puma 2.4 HT Corris Grey
When you say the relay blew, something seems odd there. What do you mean by "blew"? Relays rarely fail due to overcurrent, it's usually the act of opening that kills them. Did a fuse blow?
Post #524831 17th Apr 2016 7:24pm
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custom90



Member Since: 21 Jan 2010
Location: South West, England.
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^^ That is what I was confused by.
I don't suppose trigger live is through the coil to light bar.
I.e.
86 trigger live to 85 light bar live.....

It should be 85 earth, 86 live trigger. ~ [coil]

30 battery permanent live, 87 light bar live. [switch]

This would be for a N/O contact 4 pin relay, these are normally 20-30-40A which all would be more than enough.
Post #524833 17th Apr 2016 7:32pm
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yorkshireman



Member Since: 28 Mar 2016
Location: North England
Posts: 80

Hi, I was advised to use the following diagram to wire them in:
https://s3-eu-west-2.amazonaws.com/i.hubnu...ddd815.jpg

I was a little unsure though as the relay isn't grounded at all. I'm assuming it's the relay that' gone.

Admin note: this post has had its images recovered from a money grabbing photo hosting site and reinstated Mr. Green
Post #524848 17th Apr 2016 8:11pm
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yorkshireman



Member Since: 28 Mar 2016
Location: North England
Posts: 80

So looking at that diagram what should actually happen is the switch should be used to simply interrupt the trigger with 30 perm / 87 Light bar live / 85 earth for both the relay & light bar. Is that correct?
Post #524849 17th Apr 2016 8:22pm
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Cupboard



Member Since: 21 Mar 2014
Location: Suffolk
Posts: 2971

United Kingdom 2011 Defender 110 Puma 2.4 HT Corris Grey
Image:

Click image to enlarge


30 is "Common", which is only really relevant on a changeover relay, but that's the load input terminal.
87 is "Normally Open" that is an output that in the rest state is not connected to anything (whereas the NC is connected to the common terminal 30).
Control is via terminals 85 and 86, because most automotive relays have nothing more than a coil it doesn't matter which way round is which +/-.

In this case, we're low side switching the relay (that's pretty normal). That is the switch is disconnecting the negative side - if you look at the picture and imagine pushing the switch down the bar will join the negative and the first terminal with the "UB" wire going to it.

The other side is the positive side, the "UW" wire. This is fed from the light that says your high beam lights are on so the relay (and by extension lightbar) will only turn on when high beam lights are on *and* the switch is pressed in. Positive supply from the warning light circuit, through the coil, through the switch to the negative.


I hope that's not too patronising but makes sense?

Back to a non working lightbar.
I think I'd be tempted to temporarily forget the relay, switches and whatever and just run it back to a battery to test it. If that works then you know the lightbar is good.

Admin note: this post has had its images recovered from a money grabbing photo hosting site and reinstated Mr. Green
Post #524866 17th Apr 2016 9:08pm
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yorkshireman



Member Since: 28 Mar 2016
Location: North England
Posts: 80

Hi not patronising at all and thanks for the explanation. Would what custom90steve suggested be a more conventional method to try. Would 'low side switching' make a difference to an LED bar as opposed to conventional lights.
Post #524872 17th Apr 2016 9:31pm
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Cupboard



Member Since: 21 Mar 2014
Location: Suffolk
Posts: 2971

United Kingdom 2011 Defender 110 Puma 2.4 HT Corris Grey
The picture above is only low side switching the relay, and it doesn't really make any difference to the function of either the relay or the lightbar.

To use an example of why you might want to use low side switching though... my compressor is run from a relay with a permanent positive and a switched negative. The worst case scenario of the remote control cable for that rubbing through to the chassis is the compressor running.

What custom90steve has suggested is a perfectly good way of switching it, but you'd miss out on some of the features of the switch. If you wanted to high side switch the relay then you can take a positive feed from some part of the main beam circuit, run that through a switch to the relay coil. Then as before a separate, fused, feed from the battery to the load side of the relay, through that to the lightbar.

The only snag is if you're using that switch it's set up for low side switching. If you connected it up the other way about none of its lights would work because they're relying on terminal 4 being a negative supply. If you connected terminal 4 to a positive supply, you could still switch the relay with it but the switch wouldn't light up.

Low side switching isn't scary, it's normal. Current needs to flow, conventionally that's from the positive, through your load to the negative. Take away any one part of that and you interrupt the flow whether that's the positive supply, the negative supply or the load - take a bulb out and the current stops flowing Whistle

The only different thing about an LED is that you need to wire it with the correct polarity, that is positive to positive, negative to negative. The D part of LED is diode which is a little electrical one way valve. If you look in the picture of the switch there is a green splodge and an orange splodge with some arrows inside them pointing upwards and two little arrows coming out the side? Those are LEDs. They allow the current to flow in the direction of the big internal arrow (to the black, negative connection) and give off some light (the little arrows) in the process.
Post #524878 17th Apr 2016 9:51pm
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custom90



Member Since: 21 Jan 2010
Location: South West, England.
Posts: 20444

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Cupboard wrote: "What custom90steve has suggested is a perfectly good way of switching it, but you'd miss out on some of the features of the switch. If you wanted to high side switch the relay then you can take a positive feed from some part of the main beam circuit, run that through a switch to the relay coil. Then as before a separate, fused, feed from the battery to the load side of the relay, through that to the lightbar".

Yep, exactly my set up to keep it simple and due to the fact have front mounted spots not a roof light bar.
Is this light bar for roof mount or front mount?

If front mount you could use my method, if roof mounted then you have to have the switch.

My main reasoning for mentioning my method was to explain the workings of a basic relay which can take a bit of head scratching to get your head around at first it did for me anyway years ago!

Basically, the on off is kept off all the time hence the normally open contact.
The coil is the actually electromagnetic switching method and once energised with a small current pulls the contact together to make the circuit and turn it on. That is the click you can hear, click on, click off.

The switch does the same job effectively as main beam triggering, and you can even have both if you wanted.

The exception is, front mounted lights you can have either or both.
The roof mount must be switched, or switched and then main beam triggered.
Post #524883 17th Apr 2016 10:04pm
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