Light bar installation help

[krusing]

You laugh now @krusing but when I was changing my little low beam bulbs the other night I put the left one in, then reconnected the battery so I could check how bright it was. While I'm moving around my car looking at the beam from different angles I suddenly noticed smoke rising from near the left headlight. I yank the battery cable off and go over the other side expecting to see that my new LED bulb had spontaneously combusted, but no... I'd forgotten to swing the big headlight bulb back in to place and it was touching the coolant overflow bottle and burning the plastic. So it's not that much of a stretch for me to set something on fire.

I don’t laugh at things like that,
That is very unfortunate.

The laughing face was the way you said/put it.

 

[krusing]

View attachment 257860
as vc listed
ensure to get a relay that can handle the load
but add a fuse inline to wire 30, size will depend on lightbar current draw
and ensure your wiring can handle the lightbar load
technically illegal without a separate switch
but i wont tell if you dont

After looking at the relay terminals again,
And the way the PO wired it in on the Adventra,

30 & 85 have a link between them, and is fused to the battery,
87 is the feed to the LED light bar,
With the negative from the LED light bar grounded at the relay on the fixing screw,
86 goes to the high beam relay,
(possibly the negative wire)

 

[vc commodore]

After looking at the relay terminals again,
And the way the PO wired it in on the Adventra,

30 & 85 have a link between them, and is fused to the battery,
87 is the feed to the LED light bar,
With the negative for the LED light bar grounded at the relay,
86 goes to the high beam relay,
(possibly the negative wire)

86 is the positive high beam wire, rather than the neg..

 

[krusing]

86 is the positive high beam wire, rather than the neg..

I thought it should be too,
But the relay doesn’t a have ground connection,
so you would assume it’s using the switched negative wire from the HB relay.

 

[vc commodore]

I thought it should be too,
But the relay doesn’t have ground connection, so you would assume it’s using the switched negative wire.

Pin 85 of the relay is the earth for the relay, rather than the earth for the light bar or the high beam wire switching

Myself, just used the nut and bolt that held the relay to the body of the car to run the earth of the relay to...

 

[krusing]

85 or 86 can be either/or as it’s just the coil terminals.
As it doesn’t have a diode to the stop the back EMF,
But I am assuming it may have a resistor inside of it.
I haven’t pulled it apart, as it not broken (yet) and I don’t need to fix it

Edit: If it did have a diode installed, the terminals would then be polarity conscious, and if the polarity was reversed, it would kill the diode and the relay may/would seem faulty with a short circuit across the coil terminals.

 

[krusing]

Further to the above comment,

The coil resistance for the 30amp relay Term 85 & 86 should be approx. 94 ohms, (without an internal resistor)
If its higher one way, and lower the other, it possibly may have a diode inside it,
However, there is Very high chance, these relays do not have a diode, unless its been modified,
Which I have seen once, where it had been modified and a diode (1N4001) was soldered [hidden] on the terminals on the underside of the bottom of the relay.

 

[vxcalais_01]

It doesn’t say separate switch.

So i take that to mean the switch may be the same switch used to turn on the high beams. But it can also be a separate switch wired up so you can turn the light bar off/on if the high beams are on…

Either way, best practice was to run the light bar directly from a fused wire off the battery and through a relay which is switched using the high beam control voltage (via another switch and relay if you choose). The theory of having a relay and separate wiring was to not overload the existing headlamp wiring which in this day and age of led globes and light bars may be less relevant

It doesn't need to be and if you can connect direct to the highbeam power cable thats it. But using the headlight cable kits with fuse makes this installation so much easier. They are like $30 odd dollars from one of those 4WD stores. Yes you have a switch, but you can hide it anywhere and just leave it on........I never use the switch on mine once its on as the high beam function activates it. I only have a small lightbar, but if i use in on the freeway then I get trucks on the opposite side high beaming me to run me off the road so it must be strong.....so good to have a switch then.

 

[vc commodore]

85 or 86 can be either/or as it’s just the coil terminals.
As it doesn’t have a diode to the stop the back EMF,
But I am assuming it may have a resistor inside of it.
I haven’t pulled it apart, as it not broken (yet) and I don’t need to fix it

Edit: If it did have a diode installed, the terminals would then be polarity conscious, and if the polarity was reversed, it would kill the diode and the relay may/would seem faulty with a short circuit across the coil terminals.

If you wish to wire a relay this way or take it apart looking for a diode, go for it....Just report back with your findings

 

[Immortality]

Here is the wiring diagram for the VT.

As mentioned earlier in this thread the factory headlights are negatively switched.