Wiring for off-road lights...Help needed!
Wiring for off-road lights...Help needed!
I have 4 130Watt each offroad lights that I just installed on my light bar. I was wondering what everyone would recommend wiring wise. Im not 100% sure on how to wire these up so if you have a guide or anything that would be great, thanks.
Kosmo
Kosmo
Originally Posted by fx4me
Do they have all the wires and relays?
Try going here and find which suits your set of lights best.
Redneckstone will chime in shortly Im sure.
Zach....he's all yours, Mr. KC master.
Try going here and find which suits your set of lights best.
Redneckstone will chime in shortly Im sure.
Zach....he's all yours, Mr. KC master.
but really you posted a good link but here this link will make it easy https://www.ranger-forums.com/forum2...7&postcount=30
look at that and if you dont understand then just ask

btw what light bar you using what brand lights? just wondering
Actually the light bar I have I found in my garage as odd as that sounds.....before I had my ranger my dad got tons of stuff from ford, and it all went in the garage....so one day I was in the attic of the garage and found a Ford OEM Cargo Rack system....so I decided to put that on and see how it works...so far its been great.
As for the lights I bought them on ebay. They didnt come with relays or anything, just 5 inches of wiring coming out of the back....
As for the lights I bought them on ebay. They didnt come with relays or anything, just 5 inches of wiring coming out of the back....
I just made this Visio drawing to help you with the wiring.

If you have four lights, you will need to do this twice. You can only do two 130 watt lights per circuit.
The other way to do it is to use the high beams to turn the off-road lights on and off. Instead of going to a switch on the dash, you tap that wire into the high beam wire under the hood. This will make the relay turn on and off with your high beams and eliminate the need for switches.

If you have four lights, you will need to do this twice. You can only do two 130 watt lights per circuit.
The other way to do it is to use the high beams to turn the off-road lights on and off. Instead of going to a switch on the dash, you tap that wire into the high beam wire under the hood. This will make the relay turn on and off with your high beams and eliminate the need for switches.
Basically my setup and I do use the high beams to trigger the offroad lights on my bumper. Man, they are great on back roads at night. I believe they have kept me from hitting deer a couple of times now -- that's worth the effort right there, lol.
Originally Posted by FireRanger

Nice diagram. However, I still don't buy the notion of stepping the wire down for the branches to the individual lights.
Originally Posted by rwenzing
If you decide that 10~12 gauge is what you need to use from the fuse to the relay contacts, I would recommend that you continue using that same gauge on the two branches that serve the lights. The reason is that if you have a partial short to ground on either of the branches, then most of the maximum current that the fuse will allow can take that path. So the wire size and fuse should be selected together for the max amperage that could possibly take that path, not the current that is expected to take the path in the best of circumstances.
IMO, if you use 14~16 gauge wire anywhere in a circuit protected by a fuse sized for 10~12 gauge, the circuit is not properly protected.
IMO, if you use 14~16 gauge wire anywhere in a circuit protected by a fuse sized for 10~12 gauge, the circuit is not properly protected.
It just makes the wiring easier to install, Bob. Sometimes I do it, and sometimes I don't -- but 10 ga. is kind of clunky, so it's nice to "bus" to the location using it, then "branch" to the loads using a suitable wire size that's easier to run and terminate.
For the reasons you cited, the branches should be SHORT (short circuits, lol?) and then when there is a short, the branch wiring will allow enough current to flow to blow your disconnect (fuse or circuit breaker). Generally, the short branches don't have enough total resistance (because basically we're looking at ohms/unit length) to limit the flow below where the disconnect will fire.
For the reasons you cited, the branches should be SHORT (short circuits, lol?) and then when there is a short, the branch wiring will allow enough current to flow to blow your disconnect (fuse or circuit breaker). Generally, the short branches don't have enough total resistance (because basically we're looking at ohms/unit length) to limit the flow below where the disconnect will fire.
Originally Posted by n3elz
It just makes the wiring easier to install, Bob. Sometimes I do it, and sometimes I don't -- but 10 ga. is kind of clunky, so it's nice to "bus" to the location using it, then "branch" to the loads using a suitable wire size that's easier to run and terminate.
For the reasons you cited, the branches should be SHORT (short circuits, lol?) and then when there is a short, the branch wiring will allow enough current to flow to blow your disconnect (fuse or circuit breaker). Generally, the short branches don't have enough total resistance (because basically we're looking at ohms/unit length) to limit the flow below where the disconnect will fire.
For the reasons you cited, the branches should be SHORT (short circuits, lol?) and then when there is a short, the branch wiring will allow enough current to flow to blow your disconnect (fuse or circuit breaker). Generally, the short branches don't have enough total resistance (because basically we're looking at ohms/unit length) to limit the flow below where the disconnect will fire.
Melting the fuse because of a short assumes an adequate current flow to ground. In the possible instance of a partial short to ground (water in a light, for example), the fuse may not melt and the shorted wire could carry a current approaching the fuse's rating. I'm not saying that this is a likely scenario but stepping the wire size down for the branches is not good practice. You won't find a branch wire sized for less than the fuse rating anywhere in the truck's factory wiring.
No, you're right and it's a point taken. However, one should design for this.
The danger of fire is also dependent on location and so on. Often, the branch wires in applications like this have no real danger of starting a progressive fire.
In the case of the example posted, running just two lights on branches should allow one to do this without a lot of risk (I haven't looked up the actual examples amp capacities for the wires, or typical resistances).
But once again, the point is to design appropriately. A smaller gauge wire CAN carry a higher current for a short distance safely than it can a LONG distance. But one should NOT just arbitrarily use ANY thinner wire, but should instead DESIGN for it.
I was not defending this example specifically, just the idea of smaller wires on branch circuits. You can find examples of that being done from the factory in our trucks, however, the gauges are adequate for their length, I'm sure.
And one more thing: one occasionally OVERSIZES the buss wire to minimize voltage drop, and not for "safety reasons". So, in such cases, you will see the fuse way below the rating the buss wire can potentially carry -- but you still use a big wire for the long run to minimize resistance.
The danger of fire is also dependent on location and so on. Often, the branch wires in applications like this have no real danger of starting a progressive fire.
In the case of the example posted, running just two lights on branches should allow one to do this without a lot of risk (I haven't looked up the actual examples amp capacities for the wires, or typical resistances).
But once again, the point is to design appropriately. A smaller gauge wire CAN carry a higher current for a short distance safely than it can a LONG distance. But one should NOT just arbitrarily use ANY thinner wire, but should instead DESIGN for it.
I was not defending this example specifically, just the idea of smaller wires on branch circuits. You can find examples of that being done from the factory in our trucks, however, the gauges are adequate for their length, I'm sure.
And one more thing: one occasionally OVERSIZES the buss wire to minimize voltage drop, and not for "safety reasons". So, in such cases, you will see the fuse way below the rating the buss wire can potentially carry -- but you still use a big wire for the long run to minimize resistance.
I had my handy wire gauge chart in front of me while drawing that and I did actually have that in mind. For the distances this wire will be going, the 16 vs 12 gauge actually doens't have much of a functional difference as far as current draw. It is all only a few feet at most. 16 gauge can go 4 feet @ 30 amps. You couldn't do the whole thing in 16 gauge but the short piece of it will not have any problem handling the load for the short distance it is. For that reason, I put the 14-16 gauge wire on there for the sake of simplifying the installation if the user chooses to do so.
Thanks for the diagrams and everything....a few more questions will come up once I do this i know thats for sure. One thing that comes to mind is how would I split the wire coming from the relay into two different gauge wires?
Originally Posted by Kosmo04
Thanks for the diagrams and everything....a few more questions will come up once I do this i know thats for sure. One thing that comes to mind is how would I split the wire coming from the relay into two different gauge wires?
Thats the other advantage of going from 12 gauge down to 16. A yellow butt connector can take two 16 gauge wires in one end. One end goes on the 12 gauge from the relay and the two 16 gauge wires go in the other end together. Crimp. Seal with some silicone. Done.
I know, I understand that speaker wire carries a signal of a range of frequencies, and that power wire carries the power at DC, 0 Hz. I know the difference, I'm just saying that I think it would be better to just use 12ga. all the way. Less work, too.
It isn't any more work and in fact it can make for less work because of the splicing work. There won't be any added resistance nor will there be any voltage drop using 14-16 for the split off to the lights. You can't compare this to speakers where it is point A to point B and thats it.
There's always a resistance difference between wire gauges. Wether the distance is long enough to make a difference is where it matters, though. It's also cheaper to just buy 12ga. for power and then some wire for the 12v constant. It's going to cost at least 20 bucks to do it without buying 3 different gauges of wire, anyway.
I'm not bothering with this anymore. Do it how you want, I'm not saying you have to to do it one way or another. The options are there and thats why I put them in the schematic. There is no disadvantage to doing it either way regardless of what you think. End of story.




