OEM Wiring Harness w/ Aftermarket Fog Lights

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theluckyone17
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OEM Wiring Harness w/ Aftermarket Fog Lights

Post by theluckyone17 »

TL;DNR: Anyone have an idea what the stock wiring harness for the fog lights is rated for, current-wise?

Just picked up a set of Hella Optilux 2020's. Comes with both a set of fog and driving lamps, built into the same lens assembly. I'd like to use my stock fog lamp switch to activate the fog lamps, and another SPST switch to handle the driving lamps. Looking over the wiring, I've got three concerns:

1. Is the existing OEM wiring harness able to carry the load of the aftermarket fog lamps? The Hella wiring has a 15 amp fuse in line with the battery and both relays, so I imagine that the combined load of the fog and driving lights ought to be safely below 15 amp. I figure the stock fog lamps probably pull less than that, but I'd rather ask and look stupid than assume and burn my Baja.

2. The lamps share a common ground between the fog and driving lamps. If I use the existing ground wire that's in the fog lamp harness, it's going to be carrying the load of both the fog and driving lamps. Should I be okay? Is it worth the effort of playing safe and running a separate ground using the Hella provided wiring?

3.. I'd like to wire these lamps up so they'll turn off with the headlights. There's a convenient wire running to the radio (yellow & green) that should be providing 12V whenever the ignition is on. I should be able to tap off that for the driving light switch, and run the other lead from the switch out to the relay for the driving light. Sound right? And can I get away with using a vampire clip off that 12V accessory line, or should I find some way to neatly join them?
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bajaguy
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Re: OEM Wiring Harness w/ Aftermarket Fog Lights

Post by bajaguy »

So behind the fuse box under the dash there is a plug that contains only hot wires. Some are acc, some are always on, and some are on with the ign. I haven't figured out which ones do what exactly yet. When I get a voltmeter (requested as a Christmas present) I will take a better look. I will pull from the ignition wire to power a fused auxiliary port for all my added goodies... stop stealing from the little cruise control wire =D
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bajaguy
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Re: OEM Wiring Harness w/ Aftermarket Fog Lights

Post by bajaguy »

Found it! I will post a write-up when I actually do the work. The fuse box can be removed by a nut on the right and the clips on the top and bottom. Then, the plug in the back (closest to the driver's door) contains a big yellow wire. That's what you want to tap into for power. (note: this isn't fused) Pictures will come when I get my setup done.
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theluckyone17
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Re: OEM Wiring Harness w/ Aftermarket Fog Lights

Post by theluckyone17 »

Ah... that makes sense. I can tap into that yellow accessory line at the fusebox for power to the switch in the dash, and I won't be relying on some cob job piggyback off another accessory line. I can still run the "main" power for the driving lights off its own circuit and wire the fog lights up to the existing fog light circuit. That'll keep the fog light circuit OEM (excepting for the lights themselves) and the driving lights on its own separate circuit.

I like that! Thanks! [smilie=666.gif]
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bajaguy
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Re: OEM Wiring Harness w/ Aftermarket Fog Lights

Post by bajaguy »

For what it's worth, I would almost run your own wire. Its cleaner if you go through the rail next to the antenna (NA) than running the wire up from the back. I've also got mine running through the bar. From the inside, I ran the wire down through the front A pillar and to a switch on the dash. Whatever you do, don't forget to fuse it. Have fun! (I can't wait to get my Hella's hooked up!)

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theluckyone17
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Re: OEM Wiring Harness w/ Aftermarket Fog Lights

Post by theluckyone17 »

Ah... there's our confusion.

I'm going to be mounting these down low, not on the crossbars. I've got a Mudrat bumper, and the original fog lights are missing. Wiring is still there, but the lights are gone. I live right off a river, so fog is prevalent in my area... and I love driving in snow storms. I miss those down low lights at time.

I'd like to retain the functionality of the existing fog light switch/button, so I'm going to use the existing wiring for the fog lights, and just wire up a new circuit for the driving lights.
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bajaguy
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Re: OEM Wiring Harness w/ Aftermarket Fog Lights

Post by bajaguy »

That makes complete sense! haha I like your idea. The switch should be able to handle the extra amps, but I would look into it just to make sure.
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theluckyone17
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Re: OEM Wiring Harness w/ Aftermarket Fog Lights

Post by theluckyone17 »

Looks like the original fog light circuit uses a relay; the aftermarket light kit includes two relays. I'll use one of them for the driving light circuit.

I like how you ran the wiring through the rail. John Bloom had built up a rack that I've since sold off, but I kept the wiring harness and lights. I'll use it. The only thing I don't like is the power to the roof lights is run through the driver's side fender. I plan on rerouting it through the same grommet in the firewall that I run the driving light circuit through.

How much of a PITA was it to drill the mounting holes for the lights through the crossbar? I might do the same.
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bajaguy
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Re: OEM Wiring Harness w/ Aftermarket Fog Lights

Post by bajaguy »

The holes weren't hard to drill at all...but feeding the wires (soldered too) through definitely took a while. Like 5 wires don't fit very well. I recommend as small a gauge as you feel comfortable with. Getting them around through the end was easy though.
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