Negative LED light bar wiring

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Hi,

Today I wired my LED light bar according to the following diagram and using a demister button.

negative%20%20drivinglightwiring-earth_zps78nymzez.jpg


My Idea was by using this wiring philosophy I run one less wire across the firewall and I get the high beam trigger signal before the dimmer relay.
Why before the dimmer relay? I had problems with it and it's known to give problems so by wiring the led light bar with this signal if the dimmer relay goes off I still have the LED bar to light-up my way.
So the wire with high beam signal to trigger the LED bar relay is wired inside the cabin from the connector in the steering column to the button and form there to the relay in the engine bay.

And working wise everything is in order! But... when the lights are off and I press the LED light bar button the dimmer relay starts to buzz. When I go to high beam it shuts up...
I didn't like this buzzer so I disconnected it... I believe this is caused by a bad negative due to the added wiring loom...

What Am I missing? Or how can I achieve my goal of being able to trigger the LED light bar relay with high beams with no dimmer relay?

Thanks

Cheers
 
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From what I've noticed when I was around the rig, was that my wire equivalent to the purple has ~12vdc when high beam is off.
So when I press the switch I should have 12Vdc on the 86 port of the LED light bar relay and the relay stays open.

Anyway I'll check it to find where I have what and when.

Meanwhile... Keep it coming.

Thanks
 
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OP. How is your driving switch actually wired (versus the 'example' you attached)? You say you used a demister switch, but a demister (or defogger) switch is just an on/off switch, not a toggle switch (SPDT) as shown in your 'example' above.

So, provide us YOUR actual wiring drawing and maybe we can help further. Include your actual switch drawing and exactly where in the factory wiring you connected to. Your 'example' wiring is a red herring since that is NOT how you have actually wired things...

cheers,
george.
 

Steve D

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My only issue is because the 80 lights are ground switched, the illumination of the rocker switch is backwards (switch off, indicator light on, driving lights off --OR-- switch on, indicator light off, driving lights on).
Following up on this for future readers, I found out I should have used a DPST switch instead of a SPST so the light and switch operations can be wired separately.
 
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Hi,

I'm back with a actual drawing of what as been done to my car
( I Placed some numbering in the "wires" so it's easier to refer)

Negative%20Wiring_zpszvbsrccb.jpg


In the drawing that I previously posted isn't that switch ( two in - one out) a way to have two different ways of triggering the relay? Direct or trough the high beams?

Thanks for the posts so far

Cheers
 
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Here I am again, it seems that in the drawing I messed with the nº10 wire colors but that ain't important, I believe.

Mean while I took another look at the car and found that the dimmer relay buzzes when no light is on or when parking lights are, with low or high beams the buzzer goes away.
On low and beams I have 12Vdc at the connector, on high I've 0.3VDc ( residual) and in off or parking lights 0Vdc, and there for not a real negative or a open loop.
 
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Cut/scan/post here the part of the vehicle EWD that shows your headlights (in your diesel variant, since our petrol 80's are quite possibly different) and mark the EXACT wire you have spliced into for high beam 'sensing'.

... and with the switch you havet on its own wont let you give the dual function of high beam activated AND/OR switch activated LED bar. You'll likely need a diode or two to 'or' the functions together.

cheers,
george.
 
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Hi,

Negative%20Wiring%202_zpsc2nheyel.jpg


For High beam sensing I've spliced number 10 wire, which is the one that right after the light command switch in steering wheel.
This wire as 12Vdc when high beam is off but low beam is on and 0Vdc when high beam is on. By this I'm triggering the LED light bar relay trough the negative.

But when the main light command is in off or parking, if I recall properly, I've open loop and the buzzer stars.

Maybe the easiest way is to make a positive wiring, by using the 12Vdc after the dimmer relay, and add another switch or use one OFF-ON-OFF. Where one ON is form the high beam and the other ON is direct.
 
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I need to see the EWD page (of your diesel) with your headlight schematic. Our petrol 80's have a different setup than say the oz petrol 80's, so imagine the diesels are different again.

The KEY issue is where you are splicing in, since there's different points in the wiring control, especially with the courtesy light relay etc (if you have one). Maybe that's what you call your dimmer relay?

Anyhow, without he EWD page and the exact spot you spliced, I can't help you any further since my crystal ball is currently in for repair...

Since the 80's have a ground switched lighting system, it it's normal to see +12V on the 'ground' side of the bulb when it is NOT lit, what you are seeing is +12V through the resistance of the bulb filament. It only goes to ground when the headlight switch grounds that side of the bulb. The courtesy relay adds a bit of indirection since it is capable of cutting off +12V power to the headlights when it times out (though the 'flash' position will energise that relay while 'flash' is kept active (pulling on the stalk)).

cheers,
george.
 
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If you spliced at the circle I can see issues occurring. Consider that the low beam/high beam incandescent bulbs act like low value resistors. So, if they are just sitting there, unpowered, they will provide a ground path to the schematic top of the dimmer relay. If you then have your switch that is on one side +ve through your own relay then you are providing some power INTO your splice point. That will try to energise the dimmer relay and it will de-energise as it switches and back and forth and buzz.....

So, think carefully about what you are wiring to what, especially remember that the light bulbs will act as low value resistors to ground...

cheers,
george.
 
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@george_tlc ... my bad I misunderstood your words... I'll get back to my rig and re-check along with the EWD since at this time I'm not sure where I spliced the wire, drawing wise... I recall it was a thicker red and yellow ( 3rd from left, upper row) wire under the steering column near a black connector.

Anyway bellow you can find EWD

EWD_zpsmnkl8wqn.jpg


Thanks

Cheers
 
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So, with your drawing of how you wired things, you can see that your switch is in series with the coil of your relay would provide 12V into the EA2 node. Of course it's less than 12V since you have 2 relays in series so maybe 6V each (if their coil resistances are similar). Anyhow, it's not going to work properly.

You'll need to wire to the high beam 'output' of the dimmer relay (pin 2 or 4 - whichever is the high beam). Where you think you wired (EA2) is wrong, since you're affecting the coil of that relay and that's the buzzing you get when the relay isn't powered by the headlamp main relay (that then provides +12V).

cheers,
george.

EWD_zpsmnkl8wqn.jpg
 
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Hummmm I see...
But wouldn't a diode make it work if placed between the new relay and the new switch ( wire 6 in previous diagram)? Just being curious!
Regarding your explanation, if I got it right, it's better to do it the classic style. I'll need to trigger the relay using 12Vdc post dimmer relay, for example using a fuse piggy-back in the 15Amp fuse to high beam.
And for redundancy in case of a dimmer relay failure a separate circuit directly to the battery.
Something like in the following drawing

Positive%20Wiring%20Double%20power_zpsvyfi3kou.png


Or even uglier

Positive%20Wiring%20Double%20power%202_zpsradlb5je.png


Thanks for your support

Cheers
 
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The diode would still not be the right solution (in the above case) since you are still trying to splice at the ground side of the dimmer coil. It's a kludge to try and use the headlight filaments as a ground path to energise your light bar relay.

I'd take the highbeam +12V (from the fused output, near the headlamp) and feed that through a diode (anode to highbeam +12V side) to your light bar relay coil (say 85). Wire 86 of the coil to ground. Then take your switch and wire one side to +12V and the other side of the switch also to relay coil 85.

Feed +12V direct (fused) from battery to the relay contact 30, other side 87 to your LED light bar.

This should give you what you want, light bar comes on with your highbeams and/or light bar comes on with your switch. The diode prevents your switch trying to power your high beams.

This is still fairly clean wiring since you only need to feed your switch 'output' through the firewall and find a permanent +12V for the other side of the switch inside the cab (make sure it is fused).

cheers,
george.
 
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Thanks!! That's the way I should have gone since the beginning.

Regarding the diode, 12v and how much power should it support for my needs?

Cheers
 
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Thanks!! That's the way I should have gone since the beginning.

Regarding the diode, 12v and how much power should it support for my needs?

Cheers

The diode is only carrying the current to handle the coil current (likely around 0.1A for a common automotive 30/40A relay) of your added relay (when the high beams are off). So a 1A rated diode (which should be very common) will be more than sufficient. 40V or high rating is plenty.

cheers,
george.
 

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