Wiring a lot of lights, need help

Spence621

New member
I'm putting a Warn light bar, 2 kc daylighters and 2 off road lights from Harbor frieght on my 4runner. The Warn automatically grounds, so it only has positive leads. 5 chrome plated steel lights, 12 volts each.
the light bar is going on my rack (yes, a real rack this time, not pvc...) and the other four I'm not sure about yet, probably on the front bumper.
 

Spence621

New member
I guess I need to know what amperage ratings to get for stuff, like relays if i need them and switches, also the gauge of wire i should use
 

Spence621

New member
The Warn light bar is self grounding, but i'm mounting it one my roof basket that is not grounded. Can i just run a wire anywhere from the Smittybuilt light bar anywhere on the frame? where's the best place to ground?
 

Spence621

New member
There are 5 of them on one swtich, 12 volts each, not sure how many watts, but they use H3 bulbs if that helps.
 

CashMoney

I piss excellence.
That's 22 amps. You need to use a relay connected directly to the battery or a main 12v bus.

Yep like Gary said use a relay between them, probably atleast a 30amp one, or use 2 relays and put 3 lights on one relay and 2 on the other. You may wanna run a ground from the light bar straight to the battery for better performance too.
 

Gizmatical Fuquad

Well-known member
Premium Member
Keep your ground as short as is feasible, the closest body or rack mount bolt will work. Make sure to test with a multi-meter, not just a continuity checker. The higher the resistance on the ground, the higher the current load, you want it as close to zero ohms as possible. Some connection points will have resistance due to paint or other insulation material. Make the ground wire at least as big as the +12v lead or bigger. Use at least an 8ga wire for the +12v feed or bigger and definitely use a relay or two, unless you like fire in your rig.
 

rusty_tlc

New member
Keep your ground as short as is feasible, the closest body or rack mount bolt will work. Make sure to test with a multi-meter, not just a continuity checker. The higher the resistance on the ground, the higher the current load, you want it as close to zero ohms as possible. Some connection points will have resistance due to paint or other insulation material. Make the ground wire at least as big as the +12v lead or bigger. Use at least an 8ga wire for the +12v feed or bigger and definitely use a relay or two, unless you like fire in your rig.

It's pretty tough to do an accurate ground resistance measurement with a standard DVOM you really need to do a four wire set up, ie force current, measure voltage and calculate resistance from Ohms law. Most shade tree mechanics won't have the equipment to do this.

Better to just overkill the grounding. As Chris said 8ga or larger. The most common mistake I've seen is people not cleaning the paint off the body and chassis to get a metal to metal connection.
 

rusty_tlc

New member
BTW adding an auxiliary fuse block is a really good idea. It saves a lot of hacking into the OEM wire harness and gives you a nice tidy way to add fuses rather than a bunch of stupid in-line fuse holders. It will even work for stuff like radios if you mount it close to the battery so the supply lead is short.

Figure out how many new circuits you think you will want then get the next bigger fuse block, because it's a lot easier to have few extras than re-do it when you run out.
 
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