i need help wiring my offroad light bar. i have a prerunnered ranger, not streetlegal, used justr for the desert. i built a 5 light, light bar. i tried wiring it with 14guage wire and had the positve going of the wirie that runs the stock headlights so i could only turn the lightbart on if the head lights were on. but when i did this i used no relays, fuses, or anything else and it would cause my lights to strobe in a very erratic way would work for a min... then flash for 5 min then work again. i have 200 amp alternator to put in it.. but i dont think thats it, cause icut the wire an just hooked straight to battery for the day, had to see right. i am wondering if anyone can help me with a wiring diagram for this. it is 5 100w lights.... and i would like to maybe put some 130 or 160w bulbs if they make em,. any help would be great thanks.... do i need relays fuses, higher gauge wire???? please help.

 

Hmmm.. this is going to be big. I took 160watts x 5 =800 watts of load.

800 watts divided by 12 volts = 66.66 amps.

If we make use of commonly available parts, the most common automotive relay is 30 amps. You will be looking for a foglamp type relay. I was in Walmart the other day and they had a kit for foglamps that included a switch, the relay, and the wiring.

You are going to at least need two of these kits, and split the lights up. You could even use 3, but 2 would be plenty for the 100w lights you have now. You would have 300 watts(25 amps) on one relay, and 200 (16.6 amps) on the other.

Commonly available wire you can get at the parts store or Lowes is 10 gauge. It's good for 30 amps.

I have a diagram below for foglamps, and it will give you the jist of what to do, but your system will be a little different.

I would run 2, 10 gauge wires off the battery for a short distance, and use some sort of fuse holder for 2 30 amp fuses.

Coming out of the fuses I would then feed the two relays. The fuses and the relays can be mounted on the inner fender in the engine compartment next to the battery.

Coming out of the relays I would run two 10 gauge wires up to the lights, running two of the lights with one wire, and the other three with the last wire.

The coils for the relays need to be grounded on one side like the diagram shows. The other side of the coils I would tie together to one single wire. This wire can be small, since the relays do not draw much current.

This small wire can be run into the cab, and to a small switch mounted under the dash. You could then run power for the small switch from the headlight wire like you tried before. Or you could skip the under dash switch and wire the small relay coil wire directly to the headlight switch. It will not make the lights blink anymore, because the coils do not draw enough current to set the circuit breaker off in the headlight switch(that is what was happening before).