# Wiring a fog light, what could be easier?



## Bigplanz (Apr 10, 2009)

Or driving light, whatever you want to call it. Stuff like this happens every time I work on a car.


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## Nealtw (Jun 22, 2017)

Shrink sleeve over a soldered join.


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## Bigplanz (Apr 10, 2009)

Nealtw said:


> Shrink sleeve over a soldered join.


Soldering is the only way I can think of to combine two wires of such different gauges. What confuses me is why they are so different. The harness on my truck is the thick wire. Exact same harness on the junkyard truck, much thinner. Why?

And why are the + and - wires on my truck both black???


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## Nealtw (Jun 22, 2017)

Bigplanz said:


> Soldering is the only way I can think of to combine two wires of such different gauges. What confuses me is why they are so different. The harness on my truck is the thick wire. Exact same harness on the junkyard truck, much thinner. Why?
> 
> And why are the + and - wires on my truck both black???


 How many shops in China make harnesses.:wink2:


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## de-nagorg (Feb 23, 2014)

Year to year , plant to plant, FMC orders millions of items from dozens of different makers.

Then they are used up over time. 

Example, they order millions of wiring harnesses, use them for three to four years models, then order from a different maker next time, and the specs change. 

I have seen the same style tail light assembly on up to four years on their F-series. 


ED


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## ChuckTin (Nov 17, 2014)

When I did a fog/driving light on my cars I'd always wire in a relay. So the switched control wire was much smaller than the power tap. Maybe that's what you're seeing?


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## Bigplanz (Apr 10, 2009)

ChuckTin said:


> When I did a fog/driving light on my cars I'd always wire in a relay. So the switched control wire was much smaller than the power tap. Maybe that's what you're seeing?


These are factory intalled, OEM fog light/driving lights. Wiring diagram indicates they are relay controlled. Says negative is black, positive is tan with orange stripe. The socket from the junk yard is in this configuration, with thin (22 AWG?) wire. 

My truck's wiring is two black wires, thick (14 AWG?). The autozone connector is the same gauge wire as my truck (red and black lead), but the connector lock is the reverse of the bulb lock. 

How does simple stuff like this get screwed up? Good thing I am a "make it work" kind of guy. Can't go "by the book" when the book is flat out wrong.


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## carpdad (Oct 11, 2010)

I have almost zero info, but would it be figuring out the amps involved then may be you have to skip the factory wiring? May be the engineers didn't account for your lighting's draw. As noted, may be it goes to the relay only.


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## carmusic (Oct 11, 2011)

fog light are probably 35w so about 3 amp, so the 22-20awg is enough for one light (22 is rated at 3amp or more at free air rating)


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## ukrkoz (Dec 31, 2010)

Big, there ar every easy to use splicing "boxes", when you open one, and it has 2 channels for two wires, with sharp prongs. You place your wires, insulation intact, into those channels, and shut lid closed tight. Has small clip on it. When you do this, prongs pierce insulation and get to wires core itself. Done. You can used channel locks or pliers to squeeze them tight. Surely, such box has some sort of special name to it that I forgot... They are invaluable in tight places where getting tools in or else is very hard or impossible. Also, you can always undo it.


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## ukrkoz (Dec 31, 2010)

Like this:


https://www.lowes.com/pd/Utilitech-20-Count-T-Tap-Wire-Connectors/999956682


Ones I used had channels side by side but it's same principle..


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## carmusic (Oct 11, 2011)

those splices are only ok for interior use, they will not last long if exposed to any water, salt,... best splice is soldered with heatshrink (one that has glue inside)


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## Bigplanz (Apr 10, 2009)

carmusic said:


> those splices are only ok for interior use, they will not last long if exposed to any water, salt,... best splice is soldered with heatshrink (one that has glue inside)


The "scotchlok" connectors are ok for non-exposed environments. Crimped, heat shrunk connectors, covered with liquid electical tape, then wrapped with electrical tape, have always worked fine for me.


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## Nealtw (Jun 22, 2017)

Just wait the door wiring will really piss you off. I did a tailgate on a ford wagon, 20 splices.


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## ukrkoz (Dec 31, 2010)

Anyone ever checked how sump pump and floats are connected to AC in septic tank wells? Twist on caps packed with grease. THAT"S IT. That is *inside* the septic tank well, where it is as humid, as it goes, hot, and you have all kinds of vapors corroding everything yet, they last just fine. 

Just saying. Put a bit og grease into that scotchlock.... but yes, argue I not. If you want to do all the soldering and you, actually, do have liebensraum to do it - sure. Scotclocks did fine for me.


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## ron45 (Feb 25, 2014)

"" Re: Wiring a fog light, what could be easier?""


Watching you do it. :vs_laugh:


I'm sorry, I couldn't stop myself.


Just a thought.

The wires maybe an upgrade to handle hotter aftermarket lights.


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## Bigplanz (Apr 10, 2009)

ukrkoz said:


> Anyone ever checked how sump pump and floats are connected to AC in septic tank wells? Twist on caps packed with grease. THAT"S IT. That is *inside* the septic tank well, where it is as humid, as it goes, hot, and you have all kinds of vapors corroding everything yet, they last just fine.
> 
> Just saying. Put a bit og grease into that scotchlock.... but yes, argue I not. If you want to do all the soldering and you, actually, do have liebensraum to do it - sure. Scotclocks did fine for me.


I used them to wire two new windsheid washer pumps on my Villager. Sprayed liquid electrical tape on them, tucked them up out of the way and they worked fine. They are great for tight quarters. Since my foglight wiring is accessible I prefer crimped heat shrink butt connectors. With a decent ratchating crimper, they make for a very secure connection.

I don't solder anything unless it is repairing a circuit board. No way I am soldering wiring under my car. Recipe for solder splatter all over me.


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## Bigplanz (Apr 10, 2009)

Got it finished yesterday. Wires are crimped, heat shrunk and tucked away with a zip tie. Fog light works. Tip: those "wand" style Bic lighters for grills are not a good choice for heat shrinking. Slightest breeze and they blow out. Electric heat gun would have been a lot quicker.


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## Bigplanz (Apr 10, 2009)

Actually, one of those butane mini-torches would have melted that [email protected] pretty quick! Yay! More stuff to buy at HF! JK.


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