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Discussion Starter #1
I recently purchased an N-Fab pre runner light bar which holds 3 lights on it. Ive decided on the Hella Rallye 4000 lights due to some budgeting. However the wiring harness that Hella sells only wires up to two lights. Anyone know of any ways to wire up three of them to one switch? I thought Pro Comp sold one that went to three lights but their site has been down for several days now.
 

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Shooting from the hip here....without the spec sheet in front of me. I'm sure they only tell you to wire 2 lights for a reason. The wiring and switch that they supply probably can only handle the current draw of 2 lights. They are probably a high output light. If you add another there could be potential problems.
Blown fuse
Blown switch
Melting wires

However if you could post the wattage of the lights I could suggest a wire and fuse size.

I'm an electrician by trade. This is the first thing that comes to mind for me..
 
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i agree
probably the wiring is sized for 2 lights and i would want to know the wire size ad what the wattages are before i added a 3rd light.
as stated could even exceed the fuse rating with 3 lights.
i made that mistake many yrs ago took out 55w halogen bulbs from a set of offroad lights mounted to my bumper and dropped in the 100w halogen bulbs not giving it a thought 2 days later the wire had gotten hot enough to soften the insulation and it rubbed through on a metal edge.
had to rewire the whole setup after that to make the story short !
 

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Easy fix. You should have one relay with the lights which is made to handle 2 lights.
You should be able to purchase another relay at most auto parts stores.
Follow the same instructions but only us one side of the second relay.
Solder all of your connections and shrink wrap, don't use crimp connectors, they will eventually fail from corrosion.

Be very careful how you pick up your voltage, I'd get my primary directly from the battery and your switched voltage from a source that is key activated.
There have been voltage problems with these trucks. I've gone through two batteries in 4 months with the dealer finally installing an 850CCA battery.
 

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Don't solder. It's never done in automotive applications. If you want, apply a protectant, but it's not really needed and then shrink wrap. As someone else stated, just get a second automotive relay. You will wire the coil to the switch and power/ground etc should be obvious from any diagram you find online.
 

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Discussion Starter #6
So I finally found the one on Pro Comps website. Its made for 4 lights. Pretty much two kits sold together...4 light connections 2 relays n 2 switches. Would it be possible to just use this and just not use one light connection and maybe cut the two switches off n wire all together for a single switch??
 

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So I finally found the one on Pro Comps website. Its made for 4 lights. Pretty much two kits sold together...4 light connections 2 relays n 2 switches. Would it be possible to just use this and just not use one light connection and maybe cut the two switches off n wire all together for a single switch??
Without looking at it, yes. The switch just runs a small amount of current to trigger the coils. No problems wiring multiple relays to a single switch.
 

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I disagree! First he needs to do some research and make sure he is using wire that can handle the amperage that 3 lights will draw.
2nd I have had multiple instances where corrosion has effected wiring, solder is the best way and it is final.
But I also live in an area where snow and ice means the use of a lot of salt on the roads during winter months.
 

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I disagree! First he needs to do some research and make sure he is using wire that can handle the amperage that 3 lights will draw.
2nd I have had multiple instances where corrosion has effected wiring, solder is the best way and it is final.
But I also live in an area where snow and ice means the use of a lot of salt on the roads during winter months.
It's not final. Vibrations cause it to break. Notice how no vehicle ever has soldered connections? Terminal protector is a much better solution.

He said he got a two relay setup, relays are typically 30A, no way each light is pulling more than 15A.

FYI: I'm in VT, and I would never solder anything in one of my vehicles.
 

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8.3 amps @ 12V. You could run all three through a single 30A relay no problem.
 

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100w / 12v = 8.3a
8.3a x 3 lights = 24.9a

To run that safely, you would need 10ga wire. Imho, it is just easier to run 3 separate relays and use 16 or 14 ga wire. Bigger is always better with wire sizing.
 

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Some like to live on the edge. Personally I've seen many melted wires over the years due to overloading.
I'd rather over do it then take any chances.
 

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Discussion Starter #15
So I went to the 4wheelparts store here in Charlotte to get my lights n switch today. Spoke to the guy who does all the wiring for the store and he came out and told me that the 40 amp relay that came with the 2 light wiring kit would be more than enough to handle the 3 lights. I can just wire them all to each other. And would also be able to wire them up to a single switch. Just waiting on the last light to come in from Raleigh should be tomorrow or the next day.
 

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So I went to the 4wheelparts store here in Charlotte to get my lights n switch today. Spoke to the guy who does all the wiring for the store and he came out and told me that the 40 amp relay that came with the 2 light wiring kit would be more than enough to handle the 3 lights. I can just wire them all to each other. And would also be able to wire them up to a single switch. Just waiting on the last light to come in from Raleigh should be tomorrow or the next day.
There is a lot more to consider then just weather the relay will handle the amperage.
Good luck.
FYI you do not run the power for the lights through the switch. You run power from the battery to the relay then to the lights.
All your switch is doing is supplying voltage to energize the relay.
Make sure you read you instructions and understand what you are doing.
Many of us have already had electrical issues involving these trucks eating batteries.
The computer systems on these trucks use a lot of power, if there is a problem and they see after market wiring, weather is was done by a professional or not the first thing they will do is document it and blame the problem on faulty/aftermarket wiring.
 
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